In this study, we test the effectiveness of a short news media literacy message with audiences who differ in their media literacy education. We manipulate whether individuals are exposed to a news media literacy public service announcement (PSA) immediately before viewing a political program among two groups: students enrolled in media education courses versus students in a non-media course. Findings suggest that the ability of media literacy messages to influence students' processing of the subsequent political program is conditioned by their preexisting media literacy education. This study provides insights for considering how classroom and non-classroom media literacy interventions can work together to improve media literacy.