This study investigated college-age adolescents' perceptions of closeness with their siblings, mothers, fathers, and same-sex best friends. The objective was first to determine whether a variety of activities occur in these four types of relationships, then to determine similarities and differences in the profiles for these activities across the four types of relationships. Finally, uniqueness of the activities for given relationships was explored. The activities listed on the questionnaire included items reflecting various behavioral and affective components of relationships and were subsumed under three constructs—social provisions, conflict, and dominance. The questionnaire was developed from items on existing questionnaires and items created to represent more adequately the conceptual framework of closeness. The questionnaire was successfully pilot tested resulting in a scale with a Cronbach's alpha coefficient of internal consistency of greater than .7 across all constructs for all four types of relationships. Results of the main study indicated that social provisions, conflict, and dominance exist in the four types of relationships