Purpose: Sedentary behaviour is any waking behaviour in sitting, lying or reclining postures with low energy expenditure. High sedentary behaviour levels, common after stroke, are associated with poor health and higher levels of mobility disability. The aim of this study was to undertake a behavioural diagnosis of sedentary behaviour in the early phase after stroke to inform interventions that may reduce sedentary behaviour and associated disability.Methods and materials: Independently mobile stroke survivors were interviewed three months after stroke. The topic guide was informed by the central layer of the Behaviour Change Wheel to explore three components: capability, opportunity and motivation. This model recognises that behaviour is the consequence of an interacting system of these components. Interviews were transcribed verbatim and analysed using The Framework Method.Results: Thirty one people were interviewed (66.7 years; 16 male). The perception of diminished capability to reduce sedentary behaviour due to physical tiredness/fatigue, and pain/discomfort acting as both a motivator and inhibitor to movement, were discussed. Environmental barriers and the importance of social interaction were highlighted. Perceived motivation to reduce sedentary behaviour was influenced by enjoyment of sedentary behaviours, fear of falling and habitual nature of sedentary behaviours.Conclusions: This information will inform evidence-based sedentary behaviour interventions after stroke.Implications for rehabilitationHigher levels of sedentary behaviours are associated with poor health and stroke survivors are highly sedentary.Stroke survivors have complex reasons for spending time in sedentary behaviours including fatigue, pain, fear of falling and environmental barriers.Future interventions should educate stroke survivors on the health consequences of sedentary behaviours and encourage an increased awareness of time spent sedentary.Supporting stroke survivors to identify enjoyable and achievable activities that involve standing and movement, and ideally social interaction, is recommended.