This article investigates criminal justice reform in the U.S. states through a policy learning framework. A comparative case study of reform in Texas and California reveals a policy learning process conditioned by each state’s political environment. Republicans in Texas embraced reform after conservative policy entrepreneurs framed the issue in a manner that matched lawmakers’ core ideological beliefs. Republicans received no such messages in California. With few electoral incentives to support reform, Republicans in California demonstrated little interest in learning from the policy experiences of co-partisans in earlier adopting states. Overall, the analysis shows how policy learning shapes Republicans’ relative support for criminal justice reform and the dynamic ways Republican leadership on the issue helps facilitate state policy adoption.