Information Privacy Concern About Peer Disclosure in Online Social Networks In online social networks, because one’s private information can be co-owned and disclosed by peers, a new type of privacy concern, i.e., information privacy concern about peer disclosure (IPCPD), looms large. Should a member of an online social network be offered decision control to veto ex-ante the disclosure of his/her information by peers? There has been no theoretical research on the effectiveness of decisional control to alleviate such a privacy concern. Drawing on the communication privacy management perspective and the impression management theory, this study proposes a three-way interaction effect among three important antecedents of IPCPD: 1) decisional control; 2) image discrepancy (i.e., the degree to which the disclosed information portrays an unfavorable image of the disclosed person); and 3) social network overlap between the disclosed person and the discloser. Our experimental study reveals significant findings. When image discrepancy is low, decisional control is helpful only when the social network overlap between the disclosed one and the discloser is low. When image discrepancy is high, decisional control is helpful only when the social network overlap between the disclosed one and the discloser is high. This study contributes to a theory of privacy concern aboutpeer disclosure in the context of online social networks.