BACKGROUND: South Africa is reported to have the highest burden of HIV with an estimated 8.2 million people living with HIV (PLHIV) in 2021- despite adopting the World Health Organisation (WHO) universal HIV test and treat (UTT) recommendations in 2016. As of 2021, only an estimated 67% (5.5 million) of all PLHIV were accessing antiretroviral therapy (ART), as per recorded clinic appointments attendance. Studies in sub-Saharan Africa show that people living in low-income households experience multiple livelihood-related barriers to either accessing or adhering to HIV treatment including lack of resources to attend to facilities and food insecurity. We describe the interactions between managing household income and ART adherence for PLHIV in low-income urban and semi-urban settings in the Western Cape, South Africa. METHODS: We draw on qualitative data collected as part of the HPTN 071 (PopART) HIV prevention trial (2016 - 2018) to provide a detailed description of the interactions between household income and self-reported ART adherence (including accessing ART and the ability to consistently take ART as prescribed) for PLHIV in the Western Cape, South Africa. We included data from 21 PLHIV (10 men and 11 women aged between 18 and 70 years old) from 13 households. As part of the qualitative component, we submitted an amendment to the ethics to recruit and interview community members across age ranges. We purposefully sampled for diversity in terms of age, gender, and household composition. RESULTS: We found that the management of household income interacted with people's experiences of accessing and adhering to ART in diverse ways. Participants reported that ART adherence was not a linear process as it was influenced by income stability, changing household composition, and other financial considerations. Participants reported that they did not have a fixed way of managing income and that subsequently caused inconsistency in their ART adherence. Participants reported that they experienced disruptions in ART access and adherence due to competing household priorities. These included difficulties balancing between accessing care and/or going to work, as well as struggling to cover HIV care-related costs above other basic needs. CONCLUSION: Our analysis explored links between managing household income and ART adherence practices. We showed that these are complex and change over the course of treatment duration. We argued that mitigating negative impacts of income fluctuation and managing complex trade-offs in households be included in ART adherence support programmes.