Gender mainstreaming (GM) has been on the agenda of organisations at various levels in Sweden and worldwide since the 1990s. Research has shown that GM is difficult to apply and has yet to be clearly defined, and additionally that organisations are uncertain about how to implement it. Research also suggests that the dominance of the new public management (NPM) approach within organisations has made GM work more challenging. In this article, we examine GM in a medium-sized Swedish municipality that is reorganising itself to become gender mainstreamed while introducing trust-based governance (TBG). This municipality provides a unique opportunity to study how GM is constructed in a municipality at the intersection of NPM and TBG. Applying a critical perspective, this article analyses documents from reorganisation based on Bacchi’s (2009) policy analysis. The results demonstrate that GM is mainly translated into TBG-inspired practices and that efficiency becomes an overarching concept that entangles GM, TBG and NPM. GM becomes part of cultural change together with TBG, while NPM maintains its dominance in the structural change of the organisation.