Poor mental health is a risk factor for intimate partner violence (IPV) perpetration. Literature suggests that gender differences play a role in this association. The aims of this study were to examine the: 1) prevalence of IPV perpetrated by men and women; and 2) association between symptoms of depression or posttraumatic stress disorder (PTSD) and IPV perpetration among men and women. A convenience sample of 210 people living in three peri-urban areas in South Africa completed self-report questionnaires that assessed symptoms of common mental health disorders and IPV. Gender differences were not found with regard to perpetrating physical assault and psychological aggression, although men were more likely than women to report perpetration of sexual coercion (42.9% vs. 23.8%). Men who reported higher symptoms of PTSD were 3 times (OR = 2.63, p = .023) more likely to report perpetrating sexual coercion, when controlling for demographic characteristics and symptoms of depression, than men who reported lower levels of PTSD. Women who reported moderate to severe symptoms of depression were 4 times (OR = 3.9, p = .01) more likely to report perpetrating physical assault, when controlling for demographic characteristics and symptoms of PTSD, than women who reported minimal to mild symptoms of depression. Findings add further support for differences in rates of IPV perpetration, and poor mental health as a risk for IPV perpetration. Interventions aimed at reducing IPV perpetration in the South African setting will only be marginally effective if gender-specific interventions are not developed that consider co-occurring symptoms of PTSD and depression.