Abstract Societally salient issues, like migration, stimulate user engagement with political parties on social media. This user engagement, in turn, is associated with political behavior, such as voting. Nonetheless, few studies so far have investigated the interaction between these factors. We examine how anti-immigration attitudes are associated with user engagement with political parties on social media. In this study, user engagement is understood as following political parties on social media. Through online data that were collected in October 2019 among adults (N= 1,000) in Belgium, we investigate how attitudes and user engagement are associated with voting behavior. Results suggest that attitudes towards migration are associated with user engagement with both left and right-wing parties on social media. Moreover, these attitudes and user engagement – and the interaction between the two – are related to voting behavior: being against (being in favor of) migration and following right-wing (left-wing) parties on social media is associated with a higher likelihood of voting for a right-wing (left-wing) party.