Research on academic achievement at a university has mainly focused on success and persistence among first year students. Very few studies have looked at delay or failure in the completion of a final dissertation. However, this phenomenon could affect a substantial proportion of students and has considerable costs. The purpose of the present study is to identify factors which predict postponement in the completion of the final dissertation. Several potential predictors (e.g., background, personality, social support, motivational beliefs, and engagement) were selected through an integrative review of the literature on achievement in higher education. A questionnaire assessing these variables was administered to 341 students a few months before the deadline for their final dissertation. Results indicate that perceived peer support, perceived relatives support, role conflict, and age have an independent and significant effect on whether or not the final dissertation is completed on time. In addition, self-efficacy and behavioral engagement appeared to be mediators of the relationship between the social support and the final dissertation completion.