This study examined adolescent and maternal factors of the quality of maternal homework involvement and the extent to which the factors predicted adolescents' subsequent achievement through adolescents' and mothers' perceptions of the quality of maternal homework involvement. The sample consisted of 847 Finnish adolescents and their 662 mothers who both rated the quality of homework involvement (i.e., autonomy support and psychological control) in the fall of Grade 6. Adolescents rated their positive and negative academic emotions. Mothers rated their beliefs about adolescents' school success, their positive and negative emotions, and adolescents' task avoidance in homework situations. Information on adolescents' achievement was obtained from school registers. The results showed that adolescent and maternal factors were differently associated with adolescent- and mother-perceived quality of maternal homework involvement. Moreover, higher levels of adolescent task avoidance, mothers' lower beliefs, and negative emotions predicted poorer subsequent achievement via mothers' perception of high psychological control.