Political equity advocates and academics often argue that we must elect more women, but what difference does it make if we do? What Women Represent shows that women can and do influence the issues raised and the decisions made in parliamentary debate and decision-making. Using a new framework for thinking about what it means for legislators to represent women and drawing on a database that encompasses five decades of debate in the House of Commons, Erica Rayment investigates which members of Parliament represent women and what issues they address. She then examines the role women parliamentarians played in two instances where governments threatened to curtail previous gender equality gains: the Mulroney government’s attempted recriminalization of abortion and the Harper government’s plans to cut funding and weaken the mandate of Status of Women Canada. Rayment’s analysis decisively shows that parliamentary presence matters for the representation of women’s interests; women MPs, regardless of party, are more likely to act for women and play a critical role when the rights of women are at stake. What Women Represent is the first large-scale analysis of the substantive representation of women in Canadian politics, adding depth and nuance to our understanding of issues of gender in parliamentary institutions.