This 2-year prospective study aimed to examine the predictive role of students' achievement goals (mastery-approach and performance-avoidance) on socioemotional adjustment in high school by assessing the potential mediating contribution of academic motivations. A total of 407 high school students (46% boys) were surveyed each year in Secondary 2 (Grade 8), 3 (Grade 9), and 4 (Grade 10). Results indicated that mastery and performance-avoidance goals in Secondary 2 predicted emotional adjustment in Secondary 4, and that these links were mediated by introjected regulation and amotivation in Secondary 3. In addition, performance-avoidance goals predicted social adjustment in high school, without it being mediated by motivation types. Results are discussed with respect to their implications for teacher training programmes. Limitations and future research directions are also outlined.