Given that terrorism is omnipresent on social media, it is imperative to study how seeing terror content online is related to individuals’ attitudes, behaviors, and emotions. This study investigates how exposure to terrorism on social media associates with terror-related online self-disclosure and how self-disclosure, in turn, relates to fear of terrorism. A quota-based survey of young social media users (16- to 25-year-olds; N = 864) in Germany revealed that exposure to Islamist and far-right terrorism is related to higher online self-disclosure. Political ideology moderated the relationship between exposure to far-right terrorism and online self-disclosure, but not when exposed to Islamist terrorism. Attitudinal differentiation was negatively associated with self-disclosure. Additionally, we found an interaction effect of exposure to Islamist terrorism and attitudinal differentiation on self-disclosure. Finally, the results showed that online self-disclosure was positively related to fear of terrorism. By and large, our findings highlight the relevance of social media for the levels of fear.