Social-emotional factors associated with youth aggression have largely been studied in the context of social information-processing models. The ability to accurately encode and appropriately interpret others' emotions has yet to be fully examined in the context of aggressive behavior, particularly during adolescence. Using cross-sectional data from a sample of 282 at-risk early adolescents, the present study examined associations between teacher-reported aggression and youth performance on a task assessing two components of affective theory of mind: emotion recognition and situational attribution. Results indicated that emotion recognition, but not situational attribution accuracy, was significantly associated with teacher-reported aggressive behavior. Over-recognizing anger and under-recognizing sadness were unique error patterns associated with aggression, and these associations remained significant after controlling for demographics and other key social information-processing variables. Findings suggest that difficulties with emotion processing play an important role in the social information-processing patterns observed in the context of youth aggression. Implications for preventive interventions for youth at risk of engaging in aggressive behavior are discussed. [This paper was was published in "Aggressive Behavior" v47 n2 p173-182 2021.]