Intimate partner violence (IPV) has been associated with poor mental health among people with HIV (PWH) globally. Social support may be a strategy to foster mental health among PWH. Little is known about whether the relationship between IPV and mental health differs by IPV type or level of social support. Interviews were conducted with 426 PWH initiating HIV care in Cameroon. Log binomial regression analyses were used to estimate the association between four types of IPV (controlling behavior and emotional, physical, and sexual IPV) and symptoms of depression or hazardous alcohol use, separately by IPV type and level of social support. Over half (54.8%) of respondents experienced moderate/high levels of controlling behavior, 42.0% experienced emotional IPV, 28.2% experienced physical IPV and 23.7% experienced sexual IPV. Controlling behavior was associated with greater prevalence of depressive symptoms. This relationship did not vary meaningfully by level of social support (low: aPR 2.4 [95% CI 1.2, 4.9]; high: 1.7 [95% CI 1.0, 2.7]). Emotional and physical IPV were associated with greater prevalence of depressive symptoms among those with low social support (emotional IPV: aPR 1.9 [95% CI 1.0, 3.4]; physical IPV: aPR 1.8 [95% CI 1.2, 2.8]), but not among those with high social support (emotional IPV: aPR 1.0 [95% CI 0.7, 1.6]; physical IPV: aPR 1.0 [95% CI 0.6, 1.6]). Controlling behavior, emotional IPV, and physical IPV were associated with a greater prevalence of hazardous alcohol use, with moderately larger effect estimates among those with high compared to low social support. Sexual IPV was not associated with depressive symptoms or hazardous alcohol use. Services to screen and care for people experiencing IPV are urgently needed among PWH in Cameroon. Future research to identify barriers, feasibility, acceptability, and organizational readiness to integrate IPV and mental health services into HIV care settings is needed.