In this 2-year longitudinal study (n=242), the authors examined relations of having a reciprocated friend and characteristics of a reciprocated friend to students' social and academic adjustment to middle school. With respect to having a friend, 6th-grade students without friends showed lower levels of prosocial behavior, academic achievement, and emotional distress than did students with reciprocated friendships. Not having a friend in 6th grade also was related to emotional distress 2 years later. Evidence that motivational processes mediate relations between friends' and individuals' prosocial behavior was obtained. For students with reciprocated friendships (n=173). friends' prosocial behavior predicted change in individuals' prosocial behavior in 8th grade by way of changes in goals to behave prosocially. Implications for studying friendship influence in middle school are discussed.