The transition to university can be a stressful time for emerging adults. Perfectionism is a prevalent trait in university populations and has been associated with increased likelihood of mental health problems. A year-long longitudinal study was conducted to examine whether perfectionism negatively influenced mental health in students transitioning to university. Students (N=656) were recruited prior to university and followed up with at three time-points throughout the year (October, January, April). At each time-point participants completed surveys on perfectionism, depression, anxiety, physical symptoms and stress. Using latent growth curve analyses, self-critical perfectionism was found to predispose students to experience more stress, depression, physical symptoms and anxiety before beginning university and consequently throughout the school year. Conversely, personal standards perfectionism was found to be related to decreased mental health scores at baseline. Self-critical perfectionism is a factor which predicts poor mental health adjustment in students transitioning to university.