This article investigates political disagreement on social media in comparison to face-to-face and anonymous online settings. Because of the structure of social relationships and the social norms that influence expression, it is hypothesized that people perceive more political disagreement in social media settings versus face-to-face and anonymous online settings. Analyses of an online survey of adults in the United States show that (a) social media users perceive more political disagreement than non-users, (b) they perceive more of it on social media than in other communication settings, and (c) news use on social media is positively related to perceived disagreement on social media. Results are discussed in light of their implications for current debates about the contemporary public sphere and directions for future research.