Katima Mulilo has the highest burden of HIV/AIDS in Namibia. Due to several constraints of the antiretroviral therapy programme, HIV-infected persons still use ethnomedicines to manage AIDS-related opportunistic infections. Despite the reliance on plants to manage HIV/AIDS in Katima Mulilo, there have been no empirical studies to document the specific plant species used by traditional healers to treat AIDS-related opportunistic infections. In this study, an ethnobotanical survey was conducted to record the various plant families, species, and plant parts used to manage different HIV/AIDS-related opportunistic infections in Katima Mulilo, Caprivi region, Namibia. The results showed that a total of 71 plant species from 28 families, mostly the Combretaceae (14%), Anacardiaceae (8%), Mimosaceae (8%), and Ebanaceae (7%), were used to treat conditions such as herpes zoster, diarrhoea, coughing, malaria, meningitis, and tuberculosis. The most plant parts used were leaves (33%), bark (32%), and roots (28%) while the least used plant parts were fruits/seeds (4%). Further research is needed to isolate the plants' active chemical compounds and understand their modes of action.