BACKGROUND: Primary care is increasingly focussed on the care of people with two or more long-term conditions (multimorbidity). The UK Department of Health strategy for long term conditions is to use self-management support for the majority of patients but there is evidence of limited engagement among primary care professionals and patients with multimorbidity. Furthermore, multimorbidity is more common in areas of socioeconomic deprivation but deprivation may act as a barrier to patient engagement in self-management practices. BACKGROUND: Effective self-management is considered critical to meet the needs of people living with long term conditions but achieving this is a significant challenge in patients with multimorbidity. This study aimed to explore patient and practitioner views on factors influencing engagement in self-management in the context of multimorbidity. METHODS: A qualitative study using individual semi-structured interviews with 20 patients and 20 practitioners drawn from four general practices in Greater Manchester situated in areas of high and low social deprivation. RESULTS: Three main factors were identified as influencing patient engagement in self-management: capacity (access and availability of socio-economic resources and time; knowledge; and emotional and physical energy), responsibility (the degree to which patients and practitioners agreed about the division of labour about chronic disease management, including self-management) and motivation (willingness to take-up types of self-management practices). Socioeconomic deprivation negatively impacted on all three factors. Motivation was especially reduced in the presence of mental and physical multimorbidity. CONCLUSION: Full engagement in self-management practices in multimorbidity was only present where patients' articulated a sense of capacity, responsibility, and motivation. Patient 'know-how' or interpretive capacity to self-manage multimorbidity is potentially an important precursor to responsibility and motivation, and might be a critical target for intervention. However, individual and social resources are needed to generate capacity, responsibility, and motivation for self-management, pointing to a balanced role for health services and wider enabling networks.