Social network sites (SNSs) enjoy wide popularity as platforms for social interaction. When users interact with each other, they however do not only disclose their own information, but also information about others. Users therefore do not only manage their own privacy (internal privacy), but also that of others (external privacy). Privacy concerns and their effects on disclosure behavior have been extensively examined in prior literature, but there has been little research in IS on the role of external privacy. There is a gap in research on how concerns for external privacy might affect users’ voluntary disclosure decisions and how first-hand privacy invasion experiences shape users’ concerns for external privacy. We apply external information privacy concerns (EIPC) and external social privacy concerns (ESPC) as proxies for measuring external privacy. Our research model is based on Communication Privacy Management theory, empirically validated through an online survey with 265 participants. We find that EIPC and ESPC negatively affect users’ intentions to disclose information about others. In contrast, when individuals perceive ownership of others’ information, their willingness to disclose increases. Finally, users’ own experience with privacy invasion moderates the relationship between EIPC, ESPC, and users’ disclosure intentions.