It is often assumed that adolescent girls are more socially adept than their male counterparts. However, the question of whether adolescent girls’ and boys’ close friendships differ in quality is largely unexplored in the literature. The present study aims to address this question by characterizing the development of boys’ and girls’ friendship quality across seven years of adolescence, from the ages of 13 to 19. A community sample of 184 adolescents (53% female) and their closest friends participated, and observational and self-report measures of friendship quality were collected. Growth curve analyses revealed that girls’ friendship quality grew faster in early adolescence (ages 13-16), while boys’ friendship quality grew faster in later adolescence (ages 16-19), supporting the notion that boys lag in their social development. Boys’ self-reported friendship quality was lower than that of girls across all seven years of adolescence, with the strongest difference at the age of 16. Boys’ observed friendship quality was lower than that of girls only in the middle adolescent years of 14-16; this was followed by a rebound such that boys and girls were observed to demonstrate equivalent friendship quality in late adolescence. It is evident that teens’ perceptions of their friendships may not always align with their observed friendship behaviors. However, one intriguing similarity between the self-report and observational data is the finding that boys’ friendship quality appears to drop behind girls’ most robustly in the middle adolescent years. Possible reasons for this phenomenon are discussed.