This study was designed to validate the Fear-of-Intimacy Scale (FIS) (Descutner & Thelen, 1991) with an adolescent population, with reference to both the measure's original target, a dating partner (FIS-D) and a new target of the closest same-sex friend (FIS-F). High-school sophomores (158 males and 167 females) completed questionnaires pertaining to their relationships. Strong psychometric properties of both the FIS-D and FIS-F were evidenced in this study, and construct validity was supported by associations with related constructs (e.g. loneliness) and self-report items. Notable sex differences emerged, in that males reported higher fear of intimacy in their same-sex friendships, while females indicated higher fear of intimacy in their dating relationships.