The purpose of this qualitative study was to develop a theoretical model describing the disability experienced by older adults living with HIV. Forty nine HIV positive men and women over the age of 50 years participated in in-depth qualitative interviews. Transcribed interviews were analyzed using grounded theory techniques. Uncertainty or worrying about the future was at the core of the model. Components of disability including symptoms and impairments, difficulties with day to day activities and challenges to social participation were experienced in the context of extrinsic or environmental factors (social support, stigma) and intrinsic contextual factors (positive living strategies, age). Time was an overarching component of the model. The model suggests areas for interventions to prevent or reduce disability related to the consequences of aging with HIV and improve overall quality of life.