Stability and change in students' achievement goals (AGs) are of great relevance for educational research and practice. In two separate meta-analyses, we investigated the rank-order stability (93 studies, 569 effect sizes, 54,736 students), as well as the mean-level change (157 studies, 1,170 effect sizes, 81,464 students) in AGs throughout students' academic careers (K-12 to university). We found that the average rank-order stability of AGs ([rho] = 0.51) was in the approximate range of rank-order stability reported for personality traits and other motivational constructs. Stability increased with students' grade level and decreased with increasing interval duration between measurement points. Overall, the mean levels of all AGs declined throughout K-12 (Glass's [delta] ranged from -0.15 to -0.06 per year), indicating a quantitative decrease in AGs throughout this academic stage. During the university years, only mastery-approach goals significantly declined ([delta] = -0.22 per year), indicating a qualitative decrease in AGs.