Academic performance tends to deteriorate during the transition from high school to post-secondary education. In this study, our goal was to investigate whether the degree of this performance deterioration differs across the four subtypes of perfectionism from the 2 × 2 model of perfectionism. Samples of 392 university students and 946 college students completed a perfectionism questionnaire. Their high school and first semester grades were obtained through the office of the registrar. Results of latent change analyses revealed that the grades of students decreased during the transition to university (-12%) and college (-4%). The four subtypes of perfectionism were associated with a different degree of performance deterioration and supported the four hypotheses of the 2 × 2 model of perfectionism. Both university and college students with pure socially prescribed perfectionism experienced the strongest decrease in academic performance and should be closely monitored during their transition into post-secondary education.