Halal Tourism: A Critical Review of the Development and Implementation

This research aims to comprehend the development of halal tourism by systematically reviewing articles on halal tourism using the Systematic Literature Review (SLR) method and qualitative approach. This study explores the topic of halal tourism with the objective of complementing various previous research endeavors. This study reviewed 119 articles using the keywords “halal tourism” and “Muslim-friendly tourism” within the Scopus database. This study revealed four main research streams in halal tourism literature: the definition, concept, opportunities, and implementation of halal tourism. The theoretical contributions of this study include clarifying the concept and definition of halal tourism, classifying research streams in halal tourism, and offering directions for future research through various research questions. The limitations of this study are primarily attributed to the use of the Scopus database as the primary and sole source of data and the limited scope of keywords employed.


INTRODUCTION
Tourism, as a dynamic socioeconomic and cultural force, has evolved with emerging forms, like segmented tourism, influenced by environmental adaptations (Dolničar, 2004).Halal tourism, capitalizing on religious tourism market segmentation, positions itself to cater to the anticipated rise in the global Muslim populace (Dolničar, 2004).Halal tourism is one of the latest trends that arise from the growth in the number of Muslim travelers worldwide and the rapid development of the halal industry.Halal tourism is dubbed "the new billions dollar travel trend" (Muhammad et al. 2019).Furthermore, the concept of halal tourism is also very appealing to tourists because it aligns with the prevailing values and norms.For Muslim tourists, this includes catering to specific needs and preferences, such as providing halal food, prayer facilities, gender-segregated amenities, and ensuring activities and accommodations that compliant with Islamic guidelines.Overall, the appeal of halal tourism lies in its ability to provide a travel experience offering a comfortable, convenient, and culturally enriching journey while maintaining religious integrity.This makes tourists feel safe with the presence of this concept.
Research on halal tourism began with an article by Battour, Ismail, andBattor in 2010 (Vargas-Sánchez &Moral-Moral, 2020).Despite variations in publication rates, the subject has garnered increasing scholarly attention (Rusydiana et al., 2021).This mounting interest has resulted in numerous literature reviews and bibliometric studies over the past decade (see Figure 1).This research undertakes a systematic literature review on halal tourism, emphasizing the amalgamation of primary and secondary data to address significant research voids identified from prior works.
Halal tourism's definition is contested due to its ambiguity and varied interpretations.
"Islamic tourism," "Shariacompliant," and "Muslim-friendly tourism" are often used synonymously to depict halal tourism (Rasul, 2019).Henderson (2009) employed "Islamic tourism," whereas "sharia-compliant" and "Muslim-friendly" were used by Scott & Jafari (2010) and Hen-derson (2009), affecting the concept's clarity.This variability stems from diverse interpretations of Islamic tenets and cultural standards (Rasul, 2019).In countries less acquainted with halal, introducing halal services is complex due to limited knowledge of Islamic practices (Said et al., 2022).However, as previously mentioned, despite the interchangeable use of the terms "Islamic tourism" and "sharia-compliant" on certain occasions to define tourism that prioritises halal concepts, Muslim-friendly is the most commonly used terminology and is therefore used as an additional keyword in this article.
Prior research on halal tourism often employs Systematic Literature Review (SLR) or bibliometric approaches, with eight such articles identified in the Scopus database from 2019 to 2022 (see Table 1).These studies typically span from 2010 to 2021.Despite halal tourism's nascent stage, its swift growth has birthed varied SLR perspectives.Two primary SLR viewpoints exist: one addressing general phenomena and another emphasising specific aspects.Recent works by Sofyan et al. (2022) and Idris et al. (2022) use the SLR method, concentrating on disaster/crisis management and halal tourism strategies.Rusydiana et al. (2021) similarly hone in on halal tourism indicators.Earlier research, however, provided a more expansive view, exploring definitions, concepts, opportunities, and challenges (Muhamad et al., 2019;Rasul, 2019;Vargas-Sánchez & Moral-Moral, 2019, 2020;Yagmur et al., 2020).
The highlighted articles in Table 1 examine multiple facets of halal tourism, such as its core principles (Rasul, 2019;Vargas-Sánchez & Moral-Moral, 2019, 2020), research classifications like tourist perceptions and implementation strategies (Vargas-Sánchez & Moral-Moral, 2019), and six central research themes including issues like religiosity, the rise of the halal tourism industry, and debates over its definition (Muhamad et al., 2019).Furthermore, Rasul (2019) analysed the impacts of halal tourism, categorising them into economic, sociocultural, and environmental groups.
However, these works have limitations.For example, in terms of the number of articles, Muhammad et al. ( 2019 Furthermore, the findings of these articles remain relatively general rather than specific.Rasul (2019)  This study aims to fill the gaps in previous research limitations and inform future investigations on halal tourism.We have broadened the dataset, refined research classifications, and honed our focus.Specifically, we examine halal tourism research's evolution and execution.Given the surge in publications on halal tourism, this study also presents contemporary findings in the field.Employing a Systematic Literature Review, we address several pertinent questions, including: Q1.What are the prevalent research streams in the field of halal tourism research?Q2.How has the development of these thematic areas progressed over time?Q3.Which research streams have garnered greater attention from scholars in the study of halal tourism?What are the most influential research streams in halal tourism studies, and?How has the implementation evolved over time?The layout of this article includes the methodology, results, discussion, conclusions, limitations, and directions for future research.

Systematic Literature Review
A Systematic Literature Review (SLR) is distinct from traditional reviews due to its objectivity, replicability, comprehensiveness, and structured reporting, similar to empirical research (Pradana et al., 2022).Its goal is to understand the relationships among studies by examining citation frequency (Apriliyanti & Alon, 2017).SLR guides future research by highlighting potential research areas and minimizing redundancy.High citation frequency can make certain topics seem more critical, which is a limitation acknowledged by Alon et al. (2021).This SLR focuses on halal tourism research to provide a comprehensive field view.The method requires thorough database searches to ensure that all relevant halal tourism literature is considered while addressing the research questions.However, it takes a significant amount of time to review all databases in detail, making it one of the weaknesses of this method.

Data Inclusion and Exclusion
This research employed a qualitative descriptive approach involving the reading, mapping, and analysis of all articles containing the keywords "halal tourism" and "Muslim-friendly tourism," considered the most commonly used terminologies available in the Scopus database.The selection of Scopus as the database is based on the reputation and credibility of the journals indexed within it.Scopus is renowned for its stringent standards in the peer-review process and article selection, thus earning a strong reputation in the academic world.
The criteria for including research articles were defined with certain restrictions, including articles of journal type and written in English.The inclusion and exclusion criteria were determined through an initial search that required articles included in the study to meet the following criteria: (a) publication in peer-reviewed journals, (b) written in English, and (c) utilizing the keywords "halal tourism" and "Muslim-friendly tourism."No restrictions were placed on the publication year of the journal.All articles primarily focusing on halal tourism were included.In contrast, those with a primary focus outside of halal tourism, such as the halal industry, halal hotels, and halal food, were excluded.These stages were conducted using the PRISMA method.Introduced in 2009, PRISMA was designed to assist systematic reviewers in transparently reporting why a review was conducted, what the authors did, and what they found.In this literature review, PRIS-MA is utilised to strengthen the criteria for the articles under consideration to ensure they meet the specified qualifications, namely: (a) focusing on halal tourism as the primary theme, (b) written in the English language, and (c) are articles and journal publications.
By using the Scopus database and the keywords "halal tourism" and "Muslimfriendly tourism," a total of 232 studies were initially identified.However, when limited to research in the form of articles and journals, the number of studies was reduced to 169.Subsequently, a secondary search process was conducted, which involved elimi-nating studies that did not primarily address halal tourism as a theme.This resulted in 119 studies that met the established qualifications (see Figure 2).

Countries, type of tourism and the context
The findings of the qualitative analysis based on 223 articles on halal tourism indicate that a majority of the studies were carried out in Indonesia (62/37.6%)and Malaysia (40/24.2%),China (11/6.7%),Turkiye (11/6.7%)and Uni Arab Emirates (11/6.7%).This observation suggests that halal tourism research development is primarily influenced by Muslim countries' perspectives (e.g., Indonesia, Malaysia), potentially introducing institutional biases against non-Muslim countries.Meanwhile, in terms of type and context, halal tourism is still carried out as part of conventional tourism with var-  ious adjustments and mostly occurring at the management level.This is due to the fact that research on halal tourism itself is still very new.

The research streams and their categorization
The findings of this study grouped halal tourism research into four key themes: the (a) definition, (b) concept, (c) opportunities (challenges and future), and (d) implementation of halal tourism, each with sub-themes (illustrated in Figure 3).These themes and related primary questions helped categorise the research areas within halal tourism, pinpointing trends.For clarity, "definition" and "concept" are distinct themes with unique sub-themes."Definition" discusses halal tourism principles and has two sub-themes: academia and practitioners."Concept" delves into halal tourism development, like communication and marketing strategies, producing sub-themes about its application by various tourism stakeholders.

a. Definition
The main question within this research theme is, "What is the appropriate terminology and definition to be used for halal tourism?" Rasul (2019) stated that creating halal as a tourism deliverable and keeping it in tune with the Islamic ethos can be very different from just ensuring halal food because halal tourism should address many perceivable and non-perceivable aspects of Sharia (Islamic Teaching).Therefore, the definition used to explain the terminology in question must be clear and easily understood by the general public.This is important to eliminate the ambiguity of halal tourism.
In this theme, there exist two primary perspectives in defining halal tourism, name-  2020).However, some recent literature review studies indicate that the research focus is shifting towards more specific phenomena, leading to the belief that the debate over the definition and terminology of halal tourism has been resolved.According to Junaidi (2020), instead of positioning themselves solely as Sharia-compliant businesses, tourism stakeholders are increasingly opting to be more Muslim-friendly businesses.

b. Concept
The primary question that can be identified within this theme is, "How can the concept of halal tourism be applied to accommodate the needs of Muslim travelers?"We decided to categorize this theme separately from the definition theme because the concept can be interpreted more broadly, not solely confined to the definition of terminology.The debate over the concepts that can be applied in the implementation of halal tourism is also derived from the debate on how to define halal tourism itself, specifically regarding whether it should be implemented strictly based on halal principles or adjusted to specific conditions in a country.
Research within this theme can offer various new concepts for the application of halal tourism in different countries.For example, Zulkifli et al. (2011), who attempted to build a framework for halal-friendly tourism in Malaysia.Additionally, there is the introduction of an ecotourism model based on social capital in Lombok, Indonesia (Wildan & Sukardi, 2018), as well as an analysis of factors influencing halal tourism, enabling the formulation of development strategies that align with specific needs (Junaidi, 2020).The various concepts pro-

c. Opportunity (Challenge and Future)
The primary question within this theme is, "How can stakeholders leverage the potential of the halal tourism market to establish a high-quality tourism segment that is well-received by society?"Stakeholders are challenged to provide a positive response to build the framework for developing halal tourism as one of the modern tourism concepts aligned with the concept of sustainable tourism.With the emergence of the Covid-19 pandemic in recent years, the concept of halal tourism has garnered increased interest and is seen as capable of accommodating various adjustments required in the development of tourism during the pandemic era.This includes implementing strict health protocols that align with the sanitation principles within the halal tourism concept.Wardi & Trinanda (2022) have found that the halal reputation of a tourist destination significantly influences tourists' decisions to revisit that destination.Furthermore, the rigorous implementation of health protocols can make travellers feel comfortable and reduce their concerns about the virus, enhancing their overall experience.
In the context of sustainable tourism, stakeholders are also expected to be more conscious of the factors that support the concept of halal tourism.Rhama (2022) reviews how halal tourism can be a supporter of sustainable tourism programs, while Riandari et al. (2022) mention that the stakeholders' awareness is crucial to ensure the continuous and sustainable development of halal tourism, aligning it with the principles of sustainable tourism.However, these researchers also emphasize that excessive stakeholders' involvement has the potential to lead to conflicts and distances that could threaten the sustainability of the entire system.Thus, stakeholders are required to consider not only how to implement sustainable halal tourism concepts but also how to manage the factors involved in the implementation process effectively.This balance between involvement and management is critical for the long-term sustainability of halal tourism.

d. Implementation
The primary question arising from research within this theme is, "What are the perceptions of tourists (especially non-Muslims) regarding halal tourism, and how can a halal tourist destination convince tourists to visit and even revisit in the future?"The concept of halal tourism presents significant challenges for development due to its influence on various social and cultural aspects, including addressing issues related to Islamophobia.Understanding how tourists, both Muslim and non-Muslim, perceive and Source: Data analysis engage with halal tourism can provide valuable insights into addressing these challenges and promoting the growth of halal tourism as a viable and welcoming concept for all travellers.
Islamophobia is one of the social constructs that poses both obstacles and challenges to the growth of halal tourism as a robust segment of modern tourism.Green (2019), as cited in Al-Ansi et al. ( 2022), defines Islamophobia as a negative portrayal received by a group of people resulting from a combination of critical issues and crises directly or indirectly related to Islamic teachings through organized media propaganda.Islamophobia is a critical element and a moderating factor that has a significant impact on the formation of perceptions, attitudes, and behaviors that directly and indirectly influence the development of halal tourism (Al-Ansi et al., 2022).Addressing Islamophobia and promoting a more inclusive and tolerant perception of Islamic culture and halal tourism is essential for its continued development and success.
Nonetheless, these challenges can be effectively addressed through the proper implementation of the halal tourism concept.Tourists' acceptance of the implementation of the halal tourism concept is generally quite positive.Several non-Muslim countries that have begun implementing halal tourism have also responded very positively to this concept (Han et al., 2019).Essentially, the application of the halal tourism concept is aimed at attracting more Muslim tourists to their countries.For example, Cuevas et al. (2022) mention an increased demand for halal services and halal products in the Philippines.This is one of the outcomes of the global development of halal tourism, where the Philippines seeks to leverage these opportunities to attract more Muslim tourists.

The development of research streams
The categorization of research themes related to halal tourism is undertaken to understand the evolution of research in halal tourism while considering the emerging patterns.Over the past decade, the advancement of research in halal tourism has occurred at a relatively rapid and progressive pace (see Figure 4).
During its early emergence, the most prevalent theme within this categorization was dominated by the themes of definition and concept.This is highly understandable given that halal tourism is a notably intricate concept, thus affording ample room for debate.Since its inception by Battour et al. (2010), who initiated the fundamental concept of Islamic Sharia as the cornerstone of halal tourism, this concept has continued to evolve and be a subject of debate.Consequently, this concept has given rise to two primary perspectives regarding its application: those of academia and those of practitioners (El-gohary, 2016;Bogan & Sarusik, 2018;Vargas-Sánchez & Moral-Moral, 2019).Practitioners propose that the implementation of halal tourism can be adapted to the specific needs and context of the place where the concept is applied, taking into consideration promotional and marketing values.However, this proposition has elicit- ed varying responses from the academic community.According to academics, the implementation of the halal tourism concept must strictly adhere to the concept of halal in its entirety, as the terminology "halal" itself holds stringent validity.Consequently, this divergence in perspective has led to varying interpretations and applications of the terminology "halal tourism" among different researchers.
Following an extended period of debate regarding the definition and concept of halal tourism, which was considered resolved with practitioners of halal tourism preferring to adopt a more Muslim-friendly concept rather than being strictly bound by Sharia compliance (Junaidi, 2020), researchers have shifted their focus towards exploring the opportunities, challenges, and the implementation of this concept.Oktadiana et al. (2016) emphasized the importance of understanding the needs of Muslim travelers, ranging from cultural norms, verbal and non -verbal communication, and life scripting, to the domain of relationships.This understanding is essential to ascertain the extent to which these needs can be accommodated to support the potential market of halal tourism.Additionally, countries with non-Muslim-majority populations have also begun to consider the halal tourism concept as a means to attract more Muslim tourists.Gabdrakhmanov et al. (2016) sought to delineate the features of Islamic tourism and the challenges involved in developing this concept in Russia.According to their analy-sis, the evolution of halal tourism and recreation necessitates a comprehensive system comprising components such as halal food, halal hotels, halal flights, halal services, Islamic banking, relevant personnel, VIP service provisions, and more.They argue that all of these aspects hinge on the initiatives of public authorities, financial institutions, and the local populace, including their attitudes towards the development of halal tourism and the emergence of halal tourists in Russia.
Furthermore, Razzaq et al. (2016) conducted research on New Zealand's capacity to accommodate the halal tourism market.Although the results were not as desired, indicating that New Zealand may not be fully prepared or capable of accommodating the halal tourism market, it is also understood that various countries have been considering the adoption of the halal tourism concept as a robust strategy for developing their tourism sector.This argument is reinforced by the research conducted by Han et al. (2019), which aimed to delineate the attributes of halal-friendly destinations in South Korea.Their study identified five fundamental attributes that a tourist destination must possess to attract Muslim travelers effectively.These attributes include: (1) a halal-friendly social environment, (2) halalfriendly facilities, (3) halal food and beverage options, ( 4) halal-friendly services, and ( 5) halal-friendly locals and staff.These five attributes can be leveraged to create a halalfriendly image for a tourist destination, Subsequently, the development of research in halal tourism has revolved around the themes of opportunities and implementation.As mentioned earlier, the theme of implementation has seen rapid growth in halal tourism research.One of the sub-themes that rapidly develops within the implementation theme is the aspect of perception, both from tourists and host countries or regions.Perception is a crucial aspect in the development of any discourse.Halal tourism, being a discourse, greatly relies on positive perceptions from tourists.Favorable perceptions of a tourist destination can lead to satisfaction, thereby fostering a desire to return or spread positive word-of-mouth recommendations.In their research, Mohammed et al. (2022) stated that halal attitudes, subjective norms, halal image, halal values, halal safety and security, and halal information trust significantly and positively influence the intention to recommend to others.Similar findings were also mentioned by Rahman et al. (2022), highlighting that travel quality significantly affects tourist satisfaction, which in turn directly influences word-of-mouth (WoM) recommendations for the respective destination.
In general, research development on the topic of halal tourism has progressed significantly and extensively.The evolution of research themes has continued to advance.However, from our categorization of research themes, it can be observed that the developmental pattern begins with debates regarding the definition and concept of halal tourism.Analyses of opportunities, challenges, and the implementation of the halal tour-  How can formal halal criteria standards be implemented to minimize dilemmas faced by tourism operators?(Junaidi, 2020b)  How to build a sustainable halal tourism concept and an integrated development policy to address the apathetic and reluctant attitudes of halal tourism stakeholders?(Biancone et al., 2019) Opportunity  How can tourism operators leverage the halal tourism market by maximizing the role of halal entrepreneurs?(M.Battour et al., 2022c)  How to enhance the perceived value of halal tourism for tourists?(Rodrigo & Turnbull, 2019)  How to utilize the aspect of halalness in terms of building the post-Covid-19 tourism?

Implementation
 What are the perceptions, feelings, attitudes, and behaviors of host community residents who are not directly involved in Muslim activities and their openness to collaborate with Muslim travel companies?(Al-Ansi et al., 2022b)  How to ensure that tourists receive accurate and relevant information about halal tourism to enhance the efficiency and effectiveness of its implementation?(Said et al., 2022)  How to ensure that the attributes of halal tourism are available at prominent tourist destinations by exploring dimensions such as family preferences, Muslim culture, and festivals?(Han, Al-Ansi, Koseoglu, et al., 2019b) Adinda, Kusumasari, Hadna & Susanto -Halal Tourism: A Critical Review of the Development... Source: Data analysis ism concept itself subsequently follow this.These themes are fundamentally synergistic, allowing one theme to complement and support the development of another.Such interdependence is what makes these themes unable to exist independently in the realm of halal tourism research.
The research themes that have received the most attention in the study of halal tourism, the most influential research, and the development of halal tourism implementation.
In halal tourism research, multiple themes have emerged.This study categorises the research into four primary themes: definition, concept, opportunities, and implementation.These themes are further divided into sub-themes like market, viability, trend, and response under opportunities, as well as host and tourist perceptions, satisfaction, and implications under implementation.
The halal tourism discourse has seen an evolution in theme specificity.Initially, research centred around broad themes like halal tourism definition and concept.However, recent studies highlight opportunities and implementation.Sub-themes like tourist perceptions, satisfaction, and market opportunities have become central.The growing acceptance and implementation of halal tourism globally, even in non-Muslimmajority countries like Japan and South Korea, underpin this shift.These nations now leverage halal tourism to attract especially Muslim tourists (M.Battour et al., 2022).
Among the 119 articles on halal tourism found in the database, the research theme that has received the most attention is opportunity (challenge and future), with a total of 49 articles (see Figure 5).This theme specifically delves into sub-themes such as market (19 articles), response (13 articles), trend (9 articles), and viability (8 articles).Following closely is the implementation theme with 46 articles.The sub-themes include host and tourist perceptions (24 articles), tourist satisfaction (14 articles), and implications (8 articles).Additionally, two other themes can be found in the early research articles on halal tourism.The theme of concept appears in 12 articles, which are further divided into sub-themes such as government (3 articles), providers (1 article), and community/all stakeholders (8 articles).The definition theme also appears in 12 articles, divided into sub-themes of academics (6 articles) and practitioners (6 articles).
An article's influence can be inferred from its citation count.More citations suggest a higher impact.Articles typically reflect specific research streams.This study has categorized four main streams in halal tourism research: definition, concept, opportunities, and implementation.Table 2 shows the top five pivotal studies in halal tourism based on their citation counts.
As pioneers in halal tourism research, Battour et al. (2010) have accrued 101 citations.However, Han et al. (2019) 2019), with 97 citations, explored the dynamics of tourist behavior in Muslim-friendly destinations.Their findings revealed that efficient Muslim -friendly practices positively influence various determinants, ultimately shaping Muslim tourists' attitudes and future intentions.Han, Al-Ansi, Olya, et al. (2019) work aligns with the implementation theme and perception sub-theme.Two other notable studies, cited 65 times, fall within the research themes of opportunities and implementation.Therefore, it can be concluded that the implementation theme is the most influential research stream in the field of halal tourism, with the sub-theme of perceptions being the primary choice for researchers.Although it does not represent the theme with the most articles, which is the opportunity (challenge/future) theme with 49 articles, the sub-theme of perceptions offers a comprehensive insight into the implementation of halal tourism in various countries around the world.
As the most in-demand and influential theme, the development of the implementation theme is highly diverse.The implementation theme comprises three main subthemes: perception, satisfaction, and implication.Out of the total 46 articles analyzed and categorized under the theme of implementation, the majority were conducted in Indonesia, totaling 20 articles, with locations including West Sumatra, West Nusa Tenggara, Aceh, and Jakarta.Meanwhile, the remaining 26 articles, including 10 articles in global scope, are evenly distributed across several other countries, namely Malaysia (4), South Korea (4), Turkey (3), Japan (2), and one each from Taiwan, Thailand, and the United Arab Emirates (see Figure 6).
In alignment with that, this theme captures the evolution of halal tourism implementation globally.Notably, non-Muslim nations like Japan, South Korea, Taiwan, and Thailand have embraced this approach, aiming to cater to Muslim tourists' needs.Since 2017, South Korea has enforced halal tourism regulations.Marlinda et al. (2021) attributed this to bolstering public trust and fostering ties with Muslim-majority countries.South Korea's tourism sector emphasizes halal attributes, which, as Han et al. (2019) highlighted, are pivotal in crafting a desirable destination image for Muslim tourists.South Korea's halal tourism has five key attributes: social environment, facilities, food and beverage, services, and local staff.Han, Al-Ansi, Koseoglu, et al. (2019) emphasized that these attributes significantly influence Muslim tourists' travel decisions.
Similar trends have also emerged in Japan, where the development of halal tourism was initiated as early as 2014.Japan achieved notable recognition by winning the World's Best Non-OIC Emerging Halal Destination in 2016 and securing the third position as a non-OIC Muslim-friendly destination for Muslim travelers in 2019 (Sukmayadi & Effendi, 2020).Several other non-Muslim countries have also endeavored to follow a similar path concerning the development of halal tourism.For instance, Thailand, in addition to continuously developing tourist destinations with attention to halal tourism attributes, has established its own halal certification body (Dabphet, 2021).Taiwan, on the other hand, has actively promoted halal tourism as a strategic bridge to enhance its constructive relationships with Southeast Asian countries (Wardhani et al., 2021).

Future research directions and future research questions
Research on halal tourism is still in its early stages and offers ample room for exploration.Previous researchers have explicitly mentioned this.Muhamad et al. (2019) emphasized the need to identify research themes to understand the issues and areas of concern in the literature.Additionally, addressing knowledge gaps in the implementation of halal tourism in non-Muslim countries is a pressing concern.Furthermore, Vargas-Sánchez & Moral-Moral (2019, 2020) have provided an overview that future research in halal tourism will likely focus on social-political and digital economic issues.This research also identifies and compiles several key research questions from previous studies, representing each of the categorized research streams (see Table 3).
Moreover, taking into consideration the direction of future research and avoiding previously addressed research questions, as a form of novelty presented by this research, we propose several research questions that can be explored by future researchers, representing each research stream we have categorized (see Table 4).

CONCLUSION
Halal tourism is an intriguing concept on the one hand and presents numerous challenges on the other.This research aims to address the gap in systematic literature reviews (SLR) on the topic of halal tourism conducted by earlier experts (Idris et al., 2022;Muhamad et al., 2019;Rasul, 2019;Sofyan et al., 2022;Vargas-Sánchez & Moral-Moral, 2019, 2020;Yagmur et al., 2020) by examining the development of research on halal tourism and identifying patterns that have emerged from these This study contributes to a deeper and more systematic understanding of halal tourism by addressing several key questions, such as categorizing articles, developing each thematic group and direction, and determining concrete future research questions.
This study enhances the understanding of halal tourism by systematically categorizing research into four main themes: (1) definition, (2) concept, ( 3) opportunity (challenge/future), and (4) implementation.These themes capture the diverse contexts and criteria in halal tourism research.The study also maps the evolution of these themes, noting that "perceptions" within the implementation theme are most researched, but "opportunity" is slightly more influential.This study also reveals the most influential themes in halal tourism research, showing the evolution of the study focus.Notably, the "perceptions" sub-theme is highly researched, yet "opportunity (challenge/ future)" stands out as slightly more influential.This study also suggests future research directions and poses specific questions based on the four main themes, aiming to foster continuous growth and fill gaps in halal tourism research.This study has several limitations.First, this article uses Scopus as a sin-gle database.Second, this article is confined to only two keywords (halal tourism and Muslim-friendly tourism).Future research aiming to conduct a systematic literature review (SLR) on halal tourism could expand data sources to include platforms like Web of Science (WoS), EBSCO, and others, thereby enriching the database and enhancing reliability to yield more diverse findings.Additionally, the inclusion of keywords such as "Islamic tourism," "religious tourism," and others is highly recommended, as the terminology for halal tourism is often used interchangeably with these terms in various studies.
tried to clarify the ambiguity surrounding the concept of halal tourism, and Vargas-Sánchez & Moral-Moral (2019, 2020) worked on similar issues.Muhammad et al. (2019) and Yagmur et al. (2020) gave a broader overview, emphasising the growth trend in halal tourism research.Sofyan et al. (2022), Idris et al. (2022), and Rusydiana et al. (2021) worked on specific aspects of halal tourism.These constraints suggest existing research gaps in halal tourism, which future studies could address.

Figure 3 .
Figure 3.The Research Streams of Halal TourismSource: Data Analysis

Figure 4 .
Figure 4. Development of Research StreamsSource: Data analysis

Figure 5 .
Figure 5.Total Numbers of Publication of Research StreamSource: Data analysis

Figure 6 .
Figure 6.Articles of Implementation Theme by CountrySource: Data analysis