The purpose of this study is to examine and compare the informal networks of both senior woman administrators (SWAs) and athletic directors (ADs) within National Collegiate Athletic Association Division I institutions. Drawing on extant literature citing the underrepresentation of women in sport leadership positions, we incorporate a network approach to build and analyze affiliation networks of SWAs and ADs. Guided by the framework of Leadership in Networks, we argue that the social structures within which ADs and SWAs operate impact opportunities for leader emergence and leadership outcomes. By comparing the AD and SWA affiliation networks, we illustrate the differences in informal networks among men and women leaders in sport, highlighting how informal networks may contribute to the lack of women in sport leadership positions. Previous scholars have long cited an “old boys’ club” as a barrier to women achieving leadership positions, but we argue these studies have largely relied on dispositional evidence rather than methodological and analytical strategies designed specifically to examine relationships and the corresponding network structures. Our results indicate that the SWA network is far less cohesive than the AD networks, and the few women in the AD networks are largely located outside the center of the affiliation networks. Implications regarding the impact of informal networks on the underrepresented nature of women in leadership positions are discussed.