This article examines the St. James Infirmary (SJI), a nonprofit occupational health and safety clinic for sex workers in San Francisco, to consider how particular organizational spaces and practices may challenge gender ideologies in the United States—in this case, of women sex workers as "victim-criminals." Drawing empirically from multimethod qualitative research and theoretically from feminist institutionalism, I indicate how the SJI’s broader institutional context has (re)produced a victim-criminal ideology of women in prostitution. Next, I consider the SJI’s organizational emergence and operations to argue that, by deploying particular spatial-discursive practices and operational procedures, nonprofits with legacies of activism may draw from these to challenge dominant gender ideologies, even as they work alongside the broader institutional structures that promote them. Although single case studies like the SJI cannot establish broad theoretical generalizations and propositions, I use it to build knowledge and highlight important lessons about nonprofits, gender, and institutional change.