Given the pivotal place women’s movements hold in our understanding of the dynamics and evolution of gender equality policy, it is very important to have an accurate and valid measure of women’s movement change. This paper seeks to develop such a measure based on information about women’s movements gathered in the cross-national study of the partnership between women’s movements and women’s policy agencies in 13 western postindustrial democracies conducted by the Research Network on Gender Politics and the State (RNGS). First, the paper offers a way of conceptualizing women’s movement change, developed in the context of the RNGS study, through institutionalization and activism; this approach provides an alternative to conventional and limiting assumptions about the rise and fall of autonomous, protest oriented movements through cycles, stages and waves. Next, it will use the RNGS data from 43 periods between the late 1960s and early 2000s in 13 countries to map out patterns of movement change in 5 different types of mobilization structures (informal networks, protests, local movement communities and cultural centers, new organizations, and policy campaigns) and six institutions (legislatures, bureaucracies, political parties, unions, interest groups and lobbies, and academia). Patterns of mobilization will be traced over-time and across countries and relationships between activism and institutionalization will be examined as well as associations between different types of institutions and mobilization structures. The conclusion of the paper will reflect upon the extent to which these findings challenge basic assertions about women’s movement change in the social movement literature, such as, that women’s movements have been in decline since the 1970s; and, that women’s movement strength is found only through autonomous and freestanding activism. The conclusion will also discuss the benefits of this conceptualization for understanding the dynamics of gender equality policy formation.