BACKGROUND: Psychiatric comorbidity, the presence of two or more mental health disorders, has been associated with suboptimal HIV treatment outcomes. Little is known about the prevalence of psychiatric comorbidity among people with HIV (PWH) in sub-Saharan Africa. METHODS: We conducted interviews with PWH initiating HIV care in Cameroon between June 2019 and March 2020. Depression, anxiety, post-traumatic stress disorder (PTSD), and harmful drinking were dichotomized to represent those with and without symptoms of each. Psychiatric comorbidity was defined as having symptoms of two or more disorders assessed. Moderate or severe household hunger, high anticipatory HIV-related stigma, low social support, and high number of potentially traumatic events were hypothesized as correlates of psychiatric comorbidity. Bivariable log binomial regression models were used to estimate unadjusted associations between psychosocial stressors and psychiatric comorbidity. RESULTS: Among 424 participants interviewed, the prevalence of psychiatric comorbidity was 16%. Among those with symptoms of at least one mental health or substance use disorder (n = 161), the prevalence of psychiatric comorbidity was 42%. The prevalence of psychiatric comorbidity was 33%, 67%, 76%, and 81% among those with symptoms of harmful drinking, depression, anxiety, and PTSD, respectively. Among individuals with symptoms of a mental health or substance use disorder, a high number of potentially traumatic events (prevalence ratio (PR) 1.71 [95% CI 1.21, 2.42]) and high anticipatory HIV-related stigma (PR 1.45 [95% CI 1.01, 2.09]) were associated with greater prevalence of psychiatric comorbidity. CONCLUSION: Psychiatric comorbidity was common among this group of PWH in Cameroon. The effectiveness and implementation of transdiagnostic or multi-focus mental health treatment approaches in HIV care settings should be examined.