Since the 1990s, South Koreans have gained better access to the courts as a channel for pursuing social and policy change. In particular, Koreans with disabilities began using the courts to challenge discrimination, enforce their rights, and influence policymaking. Through qualitative comparative analysis of recent legal mobilization by Koreans with disabilities, this chapter investigates factors that influence when and why people mobilize the law. Drawing on sociolegal and social movement theories, it shows that explanations focused on evolving legal opportunity structures – encompassing procedural rules, statutes, and legal interpretations – can only partly explain changing patterns in legal mobilization. Explanations should also consider the ‘support structures’ for legal mobilization: lawyers, advocacy organizations, and funding.