This study sought to investigate the predictive relationship that dimensions of attachment shared with an array of indicators of psychosocial well-being and mental health in a sample of students making the transition to higher education. One hundred and thirty one students completed the Vulnerable Attachment Styles Questionnaire (VASQ) prior to enrolment in their first semester of university education. Subsequently, the students completed measures related to perceived loneliness, institutional integration, psychological need satisfaction, depressive symptoms and ways of coping during their first semester. Results suggested that higher scores in relation to the insecurity dimension of the VASQ were instrumental in predicting negative psychosocial well-being and mental health. The results discussed the key vulnerability dimensions of attachment when seeking to predict indices of psychosocial well-being and mental health.