Sex segregation, particularly one that is reinforced in the name of religion, is often blamed for fortifying gender discrimination in society as a whole. This dissertation examines this assumption in Islamic society and investigates how such segregation may actually benefit Muslim women. This dissertation specifically asks how sex segregation has been defined among Muslims in Yogyakarta (Indonesia), who holds the authority to form the definition, and how gender separation is translated into mosque spaces and internalized through societal life. Guided by postcolonial feminist theory and poststructuralist visual theory, it further questions not only how gender conceptions permeate the architectural space of the mosque but also how architectural space helps to shape the larger landscape of gender relations. The mosques of Yogyakarta, comprising Masjid Gedhe Kauman, Musalla ‘Aisyiyah, Musalla Ar-Rosyad, Masjid Keputren, and Masjid Panepen, and the ‘Aisyiyah organization (founded in the early twentieth century) provide a case study for studying how sex segregation is imposed through social and spatial practices. Using data obtained through ethnographic research (participant observation and in-depth interviews) and archival records pertaining to the establishment of these mosques, which include mosques exclusively for women and prayer spaces set aside for them within the congregational mosque, the architectural layout of the mosques is revealed as a spatial translation of the control of the gaze upon women and their sexuality. The control is a disciplinary mechanism of spatial and visual segregation that privileges men and posits the mosque as a space for men. Yet despite this apparent discrimination, segregation can also facilitate women’s access to resources in public space such as the mosque. Because the Javanese mosque as an institution provides space for the express use of women, and thus opportunities for their leadership in that context, it serves as an important political space. By examining how gender difference is accommodated and controlled in these five mosques, this dissertation seeks to provide a model of analysis in architectural studies that may be broadly applicable to promote social justice in the religious sphere.