This study investigated the extent to which intimate partner violence (IPV) is associated with antiretroviral therapy (ART) adherence among individuals receiving ART care in Johannesburg, South Africa. A two-stage purposive sampling method was used to recruit 200 men and women from two government ART sites through a cross-sectional survey. Adherence was obtained with the AIDS Clinical Trials Group (ACTG) questionnaire, exposure to IPV with the Violence Against Women Instrument (VAWI), and other demographic variables were assessed. Multiple regression analyses assessed the association between types of IPV, ART adherence, and demographic variables. Participants were predominantly female (67%), with ages ranging from 19 to 51 years ( M = 34.9). The average ART adherence was 79%, and 51% reported exposure to IPV, mostly women (67%). Multiple regression analysis showed a significant negative association between IPV and ART adherence, with adherence decreasing by 18% (β = −17.92, p < .001) among those experiencing IPV. Sexual IPV had the strongest impact, reducing adherence by 30% (β = −29.71, p < .001), followed by emotional IPV (β = −12.53, p < .001) and physical IPV (β = −9.54, p < .001). Despite controlling for age, sex, years living with HIV, and ART duration, IPV remained negatively associated with ART adherence. The study highlights the pronounced negative influence of IPV, particularly sexual IPV, on ART adherence. In line with previous studies, we recommend the prioritisation of IPV screening in ART dispensing facilities and providing targeted psychosocial support to ART users exposed to IPV, especially women.