This chapter provides an overview of the impact of ports, their terminals and their related economic sectors and activities. Despite their economic benefits, they also have negative impacts, particularly on the environment, land use and traffic. It assesses how these effects are distributed, and identifies a mismatch between negative impacts, which are mostly localised, and their benefits, which spill over to other regions. This mismatch has intensified in recent decades, due to technological, market and other developments. The concluding section of this chapter assesses future developments that could pose additional challenges to policy makers.