In this dissertation, I explore the potential for social impact hackathons to support meaningful social change. Hackathons — a long-running community practice within open-source groups, hackerspaces, technology companies, and educational settings — remain a popular style of gathering for those engaged with technology, design, and innovation work. Over the past twenty years, hackathons have also been embraced by the social change sector as a means of developing possible solutions to social issues. However, skeptics point out numerous shortcomings of hackathons, including poor problem-selection, diversity and inclusion issues around who participates, the exploitation of unpaid labor, their limited impact, and the dangers of positing purely technological solutions to sociotechnical issues. At the same time, hackathons have enormous potential as a participatory approach to both technology development and problem solving. They bring people together around a common cause, help contribute to participant skill and identity development, and have an impact on media narratives around an issue. Rather than abandoning the hackathon as a social form, this dissertation examines how the union of feminist values and participatory design approaches can mitigate these critiques and help hackathons live up to their many potentials, including as a means of making space for community innovation at centers of technology innovation. To explore this, I present four case studies of iterations on the 2014 “Make the Breast Pump Not Suck” Hackathon held over the past seven years, including one event held virtually in response to COVID-19. Drawing on these case studies, I present design tenets and principles for hackathon organizers that can be used to design events that are inclusive, equitable, and joyful.Ph.D.