In this study, mesoporous SBA-15 bifunctionalized with cetyl and amino groups (cetyl/amino-SBA-15) was successfully prepared by a post-synthesis grafting method. Detailed characterization by XRD, FT-IR, N₂ adsorption–desorption and elemental analysis confirmed that cetyl/amino-SBA-15 still retained a long-range ordered hexagonal mesostructure. Cetyl and aminopropyl groups were simultaneously functionalized on the surface of SBA-15. The adsorption capacity of cetyl/amino-SBA-15 was much higher than the arithmetic sum of those of cetyl-SBA-15 and amino-SBA-15 due to the cooperative effect of hydrogen bonding/electrostatic interaction between 4-nonylphenol (4-NP) and aminopropyl groups and hydrophobic interactions between 4-NP and cetyl groups. The effects of the dosage and mole ratio of cetyl and amino groups on the adsorption properties of cetyl/amino-SBA-15 for 4-NP were also investigated. Cetyl/amino-SBA-15 exhibited excellent adsorption capacity over a wide range of pH values and cetyl/amino-SBA-15(3.2/0.8) displayed the highest adsorption capacity up to 120 mg g⁻¹. Furthermore, cetyl/amino-SBA-15 exhibited high adsorption selectivity for 4-NP against phenol as well as high reusability, showing great potential for applications in wastewater treatment.