This dissertation examines the process of institutionalization for cultural social movement organizations, drawing on twelve months of intensive ethnographic fieldwork and archival research in four LGBT (lesbian, gay, bisexual, and transgender) Pride organizations in three cities: New York, NY, Boise, ID, and St. George, UT. Pride events are marches, parades and festivals that celebrate LGBT identity. This study focuses on activities and decision-making involved in the production of pride events throughout the year. While some social movement theorists treat institutionalization as the final stage before organizational death, this dissertation shows that institutionalization can signal organizational growth and survival. The dissertation defines and analyzes two distinct meanings for"institutionalization." First, I develop the concept external institutionalization to describe the process by which LGBT Pride organizations become regular, established actors within a community. Pride organizations, through routine activities of fundraising and resource-gathering, create instrumental ties to local and national commercial, political, and civic entities. These ties represent social capital within a community, which generates symbolic capital, or legitimacy and recognition for the sexual minority group. The term cultural resource mobilization is used to describe the process by which organizations draw on symbolic capital to decrease social marginalization. Internal institutionalization, the second meaning of institutionalization, describes the use of routine, bureaucratic procedures for decision-making and task completion for organizational goals. Contested but largely-accepted research on social movements suggests that internal institutionalization inevitably leads to oligarchy, deradicalization, and cooptation by mainstream interests. I argue that previous research has inappropriately merged the concepts of bureaucracy with democratic decision-making. My findings suggest that formal, bureaucratic structures can be more egalitarian in the diffusion of power among members--when and if democracy is deliberately built into the bureaucratic structure--than organizations based on informal structures and the bonds of friendship. I argue that internal and external institutionalization are linked--in that external institutionalization requires some degree of internal institutionalization, and tends to push a group toward developing a bureaucratic structure--but that neither of the two are necessarily the kiss of death for an organization seeking to achieve genuine cultural, social and political change through Pride organizing.