Newcomb's (1953) idea of co-orientation (interdependence between two persons' attitudes or perceptions) is used as a framework within which interpersonal perception between friends and acquaintances is examined. The principal question is whether co-orientation effects are stronger for friendship dyads than for acquaintance dyads. More specifically, the study examines the degree to which consensus, assimilation, self-other agreement, and assumed similarity differ. The social relations model is used to analyze a data set that included 16 living groups with 119 friend dyads and 1.668 acquaintance dyads. Results indicate that co-orientation effects are more pronounced in friendship dyads. The increment in co-orientation effects is largely due to similarities in the unique or idiosyncratic perceptions that people have of friendship pairs as well as the unique agreement about others that friends have with one another.