As educational interventions that integrate death issues in the school curriculum are rarely designed, implemented and evaluated, our action research (AR) project aimed at investigating the complexities of integrating the concepts of loss and grief in the primary school curriculum of Cyprus. The purpose of this paper is to identify and analyze convergences and divergences between AR and lesson study (LS), as they emerged in our project. We particularly focus on the ways that AR served to legitimate ethically and politically those aspects of the project that constituted the experimentation of lesson plans on loss and grief. The AR and LS elements of our project functioned differently and served different purposes, and we speculate that this is not irrelevant to the controversial aspects of the lesson plans' topic, namely loss and grief. The paper argues that it may be strategically important, for ethical and political reasons, to both demarcate and associate AR and LS, navigating between them, particularly if a controversial issue is involved.