A case study of reform in police governance provides an opportunity to examine how the micro-foundations of institutional change impact gender policy. The literature has established an association between institutional transformation and opportunities for gender policy change. It is clear that new actors and new rules are significant, but less is known about their interaction. Elinor Ostrom's concept of “rules-in-use” captures rules and their enactment in combination . Interviews with a new cadre of directly elected police and crime commissioners in England revealed the ways in which they worked with new institutional rules to prioritize violence against women and girls. Seven sets of rules are identified, arranged along a formal-informal continuum. Most were not specifically “about gender” but, when enacted by motivated, knowledgeable and reflexive actors, they facilitated gender policy change. A focus on micro-foundations enables the identification of institutional building blocks for gender policy change, highlighting the co-constitutive relationship between actors and rules.