The tendency to experience flow (flow proneness) is previously found to be associated with both some personality traits and engagement. In this study, we hypothesized a positive relationship between adaptive perfectionism and academic flow, a negative relationship between maladaptive perfectionism and flow, and also postulated the mediating role of academic engagement in the relationship between perfectionism and academic flow. The sample comprised 288 university students majoring in primary education. Several questionnaires were administered to assess flow in the academic domain, perfectionism, and engagement. As expected, adaptive perfectionism, namely high standards, was positively related to a higher level of academic flow, and the relationship was mediated by higher behavioral and cognitive engagement. Also as expected, maladaptive perfectionism, namely discrepancy, was negatively related to academic flow, and the relationship was mediated by negative emotional (anxious) engagement. The study provides empirical support for the relationship between academic flow and perfectionism, suggesting engagement as a possible mechanism for this relationship.