Social cognitive skills such as empathy and theory of mind are crucial for everyday interactions, cooperation, and cultural learning, and deficits in these skills have been implicated in pathologies such as autism spectrum disorder, sociopathy, and nonverbal learning disorders. Little research has examined how these skills develop after early childhood and how they may be trained. We tested the hypothesis that experience in acting, an activity in which one must step into the shoes of others, leads to growth in both empathy and theory of mind. In two studies, we followed children (elementary school aged) and adolescents (high school freshmen) receiving 1 year of either acting or other arts training (visual arts, music) and assessed empathy and theory of mind before and after training. In both studies, those receiving acting (but not other arts) training showed significant gains in empathy scores; in Study 2, adolescents receiving acting training also showed significant gains on a naturalistic measure of theory of mind, the Empathic Accuracy Paradigm. These findings demonstrate plasticity in empathy and theory of mind long past the watershed age of 3 to 4 years and suggest that both capacities are enhanced by role-playing. (Contains 3 tables.)