This Paper subjects the Parliamentary Labour Party’s women’s committee (WPLP) to a feminist institutionalist analysis, contending that the WPLP is a gendered institution (one that is ‘for women’), embedded and active within another gendered institution (the highly masculinized UK Parliament). Informed by previous research that investigated women’s parliamentary friendships (Childs 2013), it explores the way in which the Women’s PLP acts as a ‘safe space’ within Westminster (Childs 2004). Drawing on more than 30 interviews with Labour MPs, Ministers, and Chairs of the Group, alongside analysis of the minutes of the Group’s fortnightly meetings over more than a decade, it details the group’s membership, participation in meetings by internal and external attendees, its political priorities, and activities (2002-2016). In so doing, it argues that the WPLP constituted an individual and collective resource, offering succour from the masculinized practices and culture of the House proper; enabled Labour’s women MPs to better negotiate and challenge these; and acted as one site for the development and advocacy of gendered policy engendered greater women’s substantive representation. Indeed, using both qualitative and quantitative methods we are able to reconsider claims made in the extant literature regarding first the identity of New Labour’s critical actors and secondly, the ‘difference’ Labour’s women MPs made during the governments of Tony Blair and Gordon Brown. In particular, once we are able to identify ‘who’ acted for women within the WPLP and in respect of ‘what’– particular issues and interests - did they act, and how, we are better positioned to document the feminization of the political agenda, and makes some tentative suggestions relating to the feminization of government outcomes and the quality of the representation they undertook.