While there are growing concerns among Americans about widening partisan gaps, some claim that the perceptions of polarization are exaggerated. According to the theory of false polarization, people tend to assume that opposing parties are more ideologically extreme than they actually are. Hate speech expressed and disseminated through social media, which provokes anger among the audience, might be a factor that drives such heightened perceptions. Drawing on the social identity model of deindividuation effects (SIDE model) and the affect-cognition literature, this experimental study (N = 480) investigates whether exposure to hate messages on Twitter (i.e., hate tweets) targeting Whites triggers negative emotions (i.e., anger and fear), thereby increasing the perceptions of political polarization among Whites. This study also examines whether the effect of hate tweets decreases when the source is individuated with personal information disclosed on the profile. A conditional process analysis reveals that exposure to hate tweets significantly provokes negative emotions and heightens perceived polarization through anger, and that source individuation significantly moderates the anger-provoking effect of hate tweets. These findings indicate that online hate speech may have implications for political perception and anger can play a significant role in the process. The theoretical and practical implications are discussed.