One's belief about intelligence (e.g., whether intelligence is malleable or fixed) impacts academic outcomes such as academic engagement. To examine exactly how this could take place, it is worth addressing the features of the academic setting, such as many opportunities to compare oneself with other students. Indeed, social comparison may affect the relation between belief in intelligence and academic engagement. We hypothesized that the belief that intelligence is malleable (i.e., growth mindset) would be positively associated with students' academic engagement through social comparisons that are linked to comforting conclusions, while the belief that intelligence is fixed (i.e., fixed mindset) would be negatively associated with students' academic engagement through social comparisons that are linked to threatening conclusions. The results demonstrated that growth mindset was positively associated with upward identification, one type of comforting social comparison, which was in turn positively associated with academic engagement. On the other hand, fixed mindset was positively associated with threatening social comparison. Based on the results, the relation between intelligence beliefs, social comparison types, and academic engagement are discussed.