Although a goal of many aggression intervention programs is to increase children's concern (often termed sympathy or empathy) for their peers as a means of ultimately reducing aggressive behavior, there are no measures specifically of children's concern for peers who are the targets of peer aggression. A participatory action research (PAR) model was used to create a culturally-sensitive measure of urban African American children's sympathy for peers who are the targets of physical aggression, relational or social aggression, verbal aggression, and property damage. In Study 1, 40 children (M[subscript age] = 9.71 years; 47.5% female) were interviewed about the types of incidents that lead them to feel sympathy for a peer. Based upon these findings, the 15-item Peer Sympathy Scale (PSS) was developed. In Study 2, the PSS was administered to 517 children (M[subscript age] = 9.82 years; 47.4% female) to examine the psychometric properties of the measure and to explore the association between children's sympathy for their peers and their social behavior. Greater sympathy was associated with less overt and relational aggression according to both peer and teacher reports as well as with less oppositional-defiant behavior according to teacher reports. The clinical utility of the PSS as an outcome assessment tool for social skills intervention programs is discussed.