We examined how children's peer experiences mediated the association between dispositional emotionality and academic functioning. One hundred and ninety-nine children (104 girls, Mage = 10 years) participated in a two-year study. The predictors (self-reported emotional experience, peer-nominations of emotional expressivity) and the mediators (self-reported positive and negative peer experiences) were assessed at Time 1; outcome variables (academic achievement and teacher-rated engagement) were assessed at Time 2. The effect of emotional expressivity (happiness, anger) on academic functioning was direct. The effect of emotional experience (sadness, anger) on academic functioning was indirect via negative peer experiences. The specific dimensions of emotionality (experience, expressivity) warrant consideration in the assessment of children's emotionality because they appear to have unique interpersonal mechanisms that lead to academic functioning. Beyond overt emotional expressivity, educators and caregivers should carefully attend to children's covert emotional experience in efforts to promote adaptive peer relationships and academic outcomes for children.