Adolescence is important for the development of achievement motivation, including achievement goal pursuit. Longitudinal research is scarce on adolescents' goal development and its implications for academic outcomes. In our research, we first present a systematic review of findings on achievement goals in adolescence. Then we report 2 longitudinal studies with German adolescents in which we investigated the separate as well as joint development of achievement goals, interest, and achievement in the domain of mathematics. Study 1 comprised 745 students assessed in 4 waves in grades 5-7 (43% female; age MT1 = 10.66). Study 2 comprised 1,420 students assessed in 4 waves in grades 5-8 (47% female; age MT1 = 10.58). Students reported their mastery, performance-approach, and performance-avoidance goals and their interest in mathematics. Mathematics achievement was assessed by school grades (Studies 1 and 2) and standardized test scores (Study 1). Data were analyzed using latent growth curve, multiple process, and cross-lagged models. Findings for the 2 studies evidenced a substantial degree of consistency. All goals decreased and the decrease became smaller over time in most instances. Controlling for nonfocal goals and demographic variables (socioeconomic status, gender), multiple process models revealed that change in mastery and performance-approach goals was positively related or unrelated to change in interest and achievement, whereas change in performance-avoidance goals was negatively related or unrelated to change in interest and achievement. Cross-lagged models revealed that relations between the achievement goals on the one hand and interest and achievement on the other hand were reciprocal rather than unidirectional. (PsycINFO Database Record (c) 2020 APA, all rights reserved).