This study examined time-lagged associations in achievement goals among students transitioning from elementary to middle school by complementing traditional cognitively focused approaches to include individual-level social interdependence orientations (cooperative and competitive attitudes) toward peer relations in the learning context. Using structural equation modeling, we analyzed how mindsets (growth and fixed) and social interdependence attitudes (cooperative and competitive) predicted achievement goals (mastery approach, mastery avoidance, performance approach, and performance avoidance). Data were drawn from the second and third waves of the Korean Education Longitudinal Study 2013 (KELS 2013), including 7,324 students (50.5% female). Results indicated that a growth mindset positively predicted subsequent mastery-approach and mastery-avoidance goals, whereas a fixed mindset negatively predicted mastery-approach goals and positively predicted performance-avoidance goals. Cooperative attitudes were positively associated with mastery goals, while competitive attitudes strongly predicted performance goals and were also positively related to mastery goals. In particular, whereas a growth mindset and cooperative attitudes consistently predicted mastery goals, competitive attitudes were primarily associated with performance goals but also showed a modest association with mastery goals, thereby providing empirical evidence that motivational orientations during the transition period are not unidirectional but exhibit more complex characteristics.