BackgroundStudents define competence according to the development of their skills and understanding (mastery) or based on comparisons with their peers (performance). Students may aim to achieve the outcome of interest (approach) or to avoid failure of not meeting their definition of competence (avoidance). Achievement goals are linked to adolescents’ cognitions, coping, stress, and potentially depressive symptoms. We conducted the first longitudinal study of the association between achievement goals and depressive symptoms in a nationally representative adolescent sample.MethodsWe analysed data from the Longitudinal Study of Australian Children. Achievement goals were measured at age 12/13, with the primary outcome (depressive symptoms) measured at ages 14/15 and 16/17 (Kindergarten only). Analyses were linear multilevel and traditional regressions, with adjustment for confounders.OutcomesWe included 3,200 and 2,671 participants from the Kindergarten and Baby cohorts, respectively. Higher mastery-approach goals were associated with decreased depressive symptoms (Kindergarten: −0·33 [95%CI: −0·52 to −0·15]; Baby: −0·29, [95%CI: −0·54 to −0·03]), and higher masteryavoidance with increased depressive symptoms (Kindergarten: 0·35, [95%CI: 0·21 to 0·48]; Baby: 0·44 [95%CI: 0·25 to 0·66]). Higher performance-avoidance goals were associated with increased depressive symptoms in the Kindergarten cohort only (Kindergarten: 0·26, [95%CI: 0·11 to 0·41]; Baby: −0·04 [95% CI: −0·27 to 0·19]). We found little evidence of an association between performance-approach goals and depressive symptoms.InterpretationIf associations reflect a causal relationship, school environments that promote mastery-approach goals, could reduce adolescent depressive symptoms.FundingSir Henry Dale Fellowship jointly funded by the Wellcome Trust and the Royal Society (Grant 223248/Z/21/Z).Research in contextEvidence before this studyThe onset of depression commonly occurs in adolescence, with evidence suggesting that the rate of adolescent depression is rising in many countries. Despite the importance of prevention, very few strategies are successful. Modifications to the school environment may lead to improvements in adolescents’ mental health, however there is little awareness over which factors to target. Achievement goals reflect differences in adolescents’ motivation to learn and how they measure their own success, have been linked to adolescents’ cognitions, ways of coping, stress, anxiety, and self-esteem. According to the goal-orientation model of depression vulnerability, they represent a potential risk factor for adolescent depression. Evidence has shown that students achievement goal orientations are influenced by the school environment, and that they are modifiable through targeted intervention. If there is a causal relationship, changing adolescents’ achievement goals may reduce depressive symptoms, however there is a lack of high quality evidence. We searched MEDLINE and PsycInfo from database inception to August 1, 2023 for studies describing the association between achievement goals and depression in adolescents. We used the search terms “achievement goal*” AND “adolescen*” OR “student*” AND “depression”, alongside searches in Google Scholar. We found only one longitudinal study, which used an unrepresentative convenience sample and did not adjust for confounders.Added value of this studyUsing longitudinal data of two nationally representative Australian cohorts, we examined the association between four achievement goal orientations with subsequent depressive symptoms in school-going adolescents. We found longitudinal evidence that mastery-approach, mastery-avoidance, and performance-avoidance goals were moderately associated with depressive symptoms independent of a range of confounders.Implications of all available evidenceOur study highlights that adolescents’ cognitions around learning and success are associated with future mental health outcomes. School environments that promote learning, development and personal growth could therefore reduce adolescent depressive symptoms, if this association were causal. School-based interventions that aim to enhance factors consistent with mastery goals (i.e., learning skills and understanding the subject, rather than assessing competence in comparison to peers) may have success in preventing depression, and trials are therefore warranted.