On 2 April 2015, the International Tribunal for the Law of the Sea (ITLOS) rendered an advisory opinion in which it held that Articles 58(3), 62(4), 94(2), 192 of the 1982 United Nations Convention on the Law of the Sea (UNCLOS) laid down a responsibility of flag States for fishing activities undertaken by private actors in the Exclusive Economic Zones (EEZs) of coastal States. In interpreting these provisions of UNCLOS, the ITLOS made reference to specific clauses in fisheries access agreements (FAAs) concluded by coastal States and flag States. This article examines in more detail the contribution of FAAs to the concept of flag State responsibility. It will first offer a brief discussion of the framework for fisheries access under national jurisdiction provided by UNCLOS and will then take a closer look at how certain provisions contained in FAAs have contributed –and could contribute in the future– to the concept of flag State responsibility in international fisheries law. The article concludes that FAAs have contributed significantly to the development of the concept of flag State responsibility for fishing activities in the past and may do so to a more limited extent in the future.