There is an argument that policing practices exacerbate HIV risk, particularly for female sex workers. Interventions that mobilize sex workers to seek changes in laws and law enforcement practices have been prominent in India and have received considerable scholarly attention. Yet, there are few studies on the strategies sex worker advocates use to modify police behavior or the struggles they face in challenging state institutions. This paper draws upon contemporary theories of governance and non-state regulation to analyze the evolving strategies of an HIV prevention non-governmental organization (NGO) and female sex worker community-based organizations (CBOs) to reform police practices in southern India. Using detailed ethnographic observations of NGO and CBO activities over a two year period, and key informant interviews with various actors in the sex trade, this paper shows how a powerless group of marginalized and stigmatized women were able to leverage the combined forces of community empowerment, collective action and network-based governance to regulate a powerful state actor, and considers the impact of the advocacy strategies on sex worker well-being.