BackgroundChild protection workers (CPWs) are regularly exposed to potentially traumatic events (PTEs), especially, aggressive behaviors from the service users. ObjectivesThis study aimed to evaluate the effects of a peer support program on the mental health and work functioning of CPWs exposed to a PTE, while considering the moderating effect of gender roles. Participants and settingParticipants were recruited in two youth social services centers (YSS) in Canada and assessed one month (n = 176), two months (n = 168), six months (n = 162), and 12 months (n = 161) following exposure to a PTE. Three groups were formed: workers from the first YSS who received peer support (intervention group), workers from the first YSS who did not receive peer support (first control group), and workers from the second YSS where no peer support program was available (second control group). MethodsLinear mixed models were used to compare the three groups across time. ResultsThe intervention group did not differ from the control groups on any outcome variables at any time points. Gender roles did not moderate any effect. However, compared with the first control group, the intervention group scored lower on masculine gender roles, suggesting that lower masculinity may facilitate help seeking behaviors. ConclusionThe results point toward the need to improve the peer support intervention, to complement this intervention with other forms of support, and to promote organizational changes that would favor the workers' well-being and facilitate their recovery following a PTE.