We explored the extent to which (1) individual transferable quotas (ITQs) may lead to changes in environmental stewardship and (2) environmental stewardship may in turn contribute to explain the success or otherwise of ITQs in meeting sustainability objectives. ITQs are an example of incentive-based fisheries management in which fishing rights can be privately owned and traded. ITQs are aimed at resolving the problems created by open-access fisheries. ITQs were proposed to promote economic efficiency, and there is growing empirical evidence that ITQs meet a number of economic and social fisheries management objectives. Even though improved stock status arises as a consequence of the total allowable catch levels implemented together with ITQs, the effect is difficult to separate from the improvement attributable to existing and new management changes. However, stock status improvements have also been attributed to increased environmental stewardship resulting from the allocation of individual fishing rights. We defined environmental stewardship as a set of normative values that private individuals may hold, and that entail perceived duties and obligations to carefully manage and use marine resources. We did not debate the success or otherwise of ITQs in meeting sustainability objectives but discussed the premise that this success may in part be a consequence of a change in fishers' environmental stewardship. In particular, because of the absence of empirical literature, we explored the theoretical effects of the introduction of ITQs in conjunction with comanagement on a change in environmental stewardship. Although psychological theory suggests that there may be a relationship, there is insufficient evidence to draw the conclusion that improved environmental outcomes are attributable to changes in stewardship ethics arising from the combined effect of allocating fishing rights and comanagement in ITQ-managed fisheries. Complexity added by the move to fewer and generally larger scale fishing operations, the concentration of ownership with processors and investors, the increasing numbers of lease fishers, and corporate membership on comanagement committees may all affect stewardship, and more research is needed to establish in which direction these effects are in fact playing out.