The aim of this paper is to assist governments in the identification of criteria for the use of fisheries subsidies, with the dual ambition of helping WTO negotiators craft new international law and providing domestic governments with useful advice as they pursue responsible fisheries subsidies policies. These two ambitions obviously overlap, but are also somewhat distinct. WTO rules cannot embody robust policy advice for fisheries managers, but can only set a few simplified (but important) legal constraints on the “policy space” governments enjoy for fisheries subsidies.