Public sexual harassment (PSH), defined as unwanted verbal or physical sexual contact in public spaces, is endemic in Egypt and Tunisia. A 2013 U.N. Women survey found that 99% of Egyptian women had been harassed, while the Center for Research, Study, Documentation and Information on Women (CREDIF) reported that 70 to 90% of Tunisian women experienced harassment between 2011 and 2015. Since 2013, new laws in both countries have facilitated criminal prosecution of harassers, and Egypt developed all-women police forces to monitor PSH during Eids. The political science literature stresses the importance of long-established feminist organizations in prompting such change, which is largely true in Tunisia but inaccurate in Egypt. My interviews suggest that activism against PSH in both countries has relied heavily on activists between the ages of 17 and 30, many of whom had never engaged in activism or joined feminist groups prior to the Arab Uprisings. Htun and Weldon’s article “The Civic Origins of Progressive Policy Change: Combating Violence against Women in Global Perspective, 1975–2005 (American Political Science Review, 2012) concludes that government action on violence against women (VAW) is most likely in countries with strong, autonomous feminist movements and effective women’s policy agencies, and where reservations placed by the country on its ratification of CEDAW (the Convention on the Elimination of All Forms of Discrimination Against Women) have been removed. Tunisia’s new PSH legislation, part of a larger anti-VAW law, can credibly be explained by this framework, as Tunisia has a strong feminist movement and effective women’s policy agency and removed its CEDAW reservations in 2014. The framework cannot account for the Egyptian case, however, as prior to the Arab Uprisings Egypt’s feminist movement was relatively weak, and Egypt still has no effective women’s policy machinery and has not removed its CEDAW reservations. I use interviews with youth activists to document the emergence and work of new anti-PSH groups in Egypt beginning in 2012 which battled PSH in the streets, public transport, and universities, and demonstrate how their activism built momentum for the criminal code amendments on PSH. While established feminist organizations were essential to the passage of PSH legislation in Tunisia, preliminary fieldwork there suggests that activism against PSH in the Tunisian Association of Democratic Women (ATFD), one of Tunisia’s best-institutionalized feminist organizations, was facilitated by the actions of young ATFD members new to activism in the post-2011 period.