Personalized learning (PL) approaches have become increasingly common across the United States. PL aims to create individual learning experiences and pathways for students. Despite its popularity, little data exists on the prevalence of PL practices and the conditions needed to support high-quality PL implementation, particularly in high schools. This report presents findings from high school teachers taken from RAND's 2018 American Teacher Panel. The findings should be useful to practitioners, professional development and support providers, researchers, and policymakers interested in understanding how high school teachers are using PL practices and which supports and resources they need to use them effectively.