OBJECTIVES: This article considers the potential of 'theories of practice' for studying and understanding varied (dis)engagement with HIV care and treatment services and begins to unpack the assemblage of elements and practices that shape the nature and duration of individuals' interactions with HIV services. METHODS: We obtained data from a multicountry qualitative study that explores the use of HIV care and treatment services, with a focus on examining the social organisation of engagement with care as a practice and as manifested in the lives of people living with HIV in sub-Saharan Africa. The dataset comprised of 356 interviews with participants from six countries. RESULTS: We noted fluctuating interactions with HIV services in all countries. In line with theories of practice, we found that such varied engagement can be explained by (1) the availability, absence and connections between requisite 'materialities' (eg, health infrastructure, medicines), 'competencies' (eg, knowing how to live with HIV) and 'meanings' (eg, trust in HIV services, stigma, normalisation of HIV) and (2) a host of other life practices, such as working or parenting. These dynamics either facilitated or inhibited engagement with HIV services and were intrinsically linked to the discursive, cultural, political and economic fabric of the participating countries. CONCLUSION: Practice theory provides HIV researchers and practitioners with a useful vocabulary and analytical tools to understand and steer people's differentiated HIV service (dis)engagement. Our application of practice theory to engagement in HIV care, as experienced by HIV service users and providers in six sub-Saharan African countries, highlights the need for a practice-based approach in the delivery of differentiated and patient-centred HIV services.