Perceived similarity of personality in same-sex friends was examined in a sample of 124 adolescents (63 girls). Adolescents rated themselves and a nominated friend (n = 42 reciprocated, 82 non-reciprocated dyads) on developmentally relevant personality items assessing autonomy, prosociality, and responsive caregiving. Results from hierarchical linear modeling and multiple regression analyses generally supported predictions: Greater perceived similarity was marginally positively associated with more favorable ratings of friendship quality and significantly negatively associated with conflict ratings in the friendship. Adolescents in reciprocated friendships rated themselves as more similar in personality and more positive in friendship quality than did non-reciprocated dyads. A mediational analysis revealed that the association between reciprocity and perceived similarity was mediated by positive friendship quality. These findings suggest that reciprocated friends' perceptions of being more similar in personality may in part be accounted for by their more favorable judgments of their friendship quality. (Contains 1 table.)