This longitudinal study was aimed to describe and understand student adjustment trajectories during the college transition. Participants came from a large random sample of Quebec high school students. They completed a multidimensional measure of adjustment at two times before entering college and at two other times after college admission. Group-based trajectory analysis showed decreased adjustment for 6% (social adjustment) to 66.1% (academic adjustment) of students over this period, versus improved adjustment for 4.5% (social adjustment) to 11.6% (emotional and academic adjustment). All changes were linear, suggesting progressive changes from Secondary 4 to the second year of college. Multivariate and contingency analyses showed that personal anxiety, academic success, and attention problems in high school were significant determinants for adjustment trajectories, and that these trajectories were subsequently related to perseverance and college graduation.