Antiretroviral therapy (ART) causes disturbances in the normal function of the endocrine system and has been associated with thyroid dysfunction in HIV patients on treatment. More data on thyroid dysfunction are needed in Zimbabwe to persuade the country program to institute routine monitoring if needed. We sought to establish if ART exposure is associated with thyroid dysfunction in HIV patients. A cross-sectional study with two comparative groups was conducted between 1 October and 31 December 2016. The participants included HIV-infected persons aged 18+ years who attended Opportunistic Infections (OI) clinics in urban areas around Bulawayo, Zimbabwe. Patient samples were tested at the Parirenyatwa Serology Laboratory in Harare, Zimbabwe. The two comparative groups were defined as cases and controls. Cases were HIV positive patients with thyroid dysfunction whilst controls were HIV positive patients without thyroid dysfunction. Participants included 100 females and 93 males who were on ART. The mean age was 34.6 (10.2) years and median age was 33.0 (43.5-68.3) years. The prevalence of thyroid dysfunction was 45.6% and all cases had hypothyroidism. Sex was not associated with thyroid dysfunction, but thyroid dysfunction was more significant in older patients (P=0.031). This study confirms that ART is associated with thyroid dysfunction in older HIV patients on ART. These results are worrying and may suggest a need for the country HIV program to establish strategies to mitigate this. It is cause for concern because the presence of an untreated thyroid dysfunction in HIV patients will worsen their prognosis.