ORIGINAL ARTICLE Is preventing peer victimization sufficient? The role of prosocial peer group treatment in children’s socioemotional development Wendy Troop-Gordon 1 | Lexie Unhjem 2 1 Auburn University 2 Purdue University Northwest Correspondence Wendy Troop-Gordon, Auburn University, Human Development and Family Studies, 210 Spidle Hall, Auburn, AL 36849. Email: wpg0006@auburn.edu Abstract Despite extensive research on the harmful effects of peer victimiza- tion, little is known about whether prosocial treatment from peers contributes to healthy socioemotional development. To address this issue, 366 third and fourth graders (170 boys; M age 5 9.34) were fol- lowed over three time points. Children completed measures of prosocial peer treatment, peer victimization, depressive affect, and friendship quality. Teacher-reports of depressive affect and peer- reports of aggression, victimization, and friendships were also obtained. Controlling for peer victimization, number of friends, and friendship quality, prosocial peer treatment negatively predicted depressive affect. For boys, prosocial peer treatment mediated the association between victimization and teacher-reported depressive affect. These findings underscore the importance of prosocial peer group treatment and the need to broaden the goals of anti-bullying interventions to include the promotion of positive peer interactions. KEYWORDS aggression, depression, peers/peer relations, prosocial behavior, victimization 1 | INTRODUCTION Stress emanating from adverse experiences in one’s peer group (e.g., rejection, social exclusion) derails physiological, cognitive, emotional, and behavioral development and contributes significantly to psychopathology and school maladjustment (Buhs, Ladd, & Herald, 2006; Malti, Perren, & Buchmann, 2010; Troop-Gordon & Ladd, 2005). Much of the work documenting these effects focuses on peer victimization, the experience of being the target of others’ harassment, ridicule, and aggression. Heightened awareness of the adverse effects of peer victimization has resulted in a proliferation of public campaigns and school-based interventions to combat bullying (Ttofi & Farrington, 2011), whose success is typically defined as a reduction of bullying behaviors and peer victimization. Diminished peer victimization, however, does not necessarily co-occur with increases in prosocial peer treatment —friendly, cooperative, and supportive behaviors from members of the peer group. Yet, prosocial peer treatment may Social Development. 2018;1–17. wileyonlinelibrary.com/journal/sode V C 2018 John Wiley & Sons Ltd | 1 Received: 23 December 2016 | Revised: 22 December 2017 | Accepted: 27 December 2017 DOI: 10.1111/sode.12283