With over five billion internet users globally, it is crucial to understand social media activism and legal change for women and girls. This insightful book examines the impact of international Twitter (now X) campaigns on domestic laws affecting women and girls. Exploring the complexities of legal change for women and girls across seven countries from Latin America to Middle East and Africa, the book offers empirical insights into the effectiveness of hashtag advocacy and sheds light on the role of social media in shaping different outcomes. This is a key resource for understanding the dynamics driving social media activism and its potential impact on the rights of women and girls worldwide.