Whilst strong evidence supports rehabilitation to improve outcomes post-stroke, there is limited evidence to guide rehabilitation in the most severely disabled group. In an era of evidence-based practice, the aim of the study was to understand what factors guide physiotherapists (PTs) and occupational therapists (OTs) to select particular interventions in the rehabilitation of physical function after severely disabling stroke. An ethnographic study was undertaken over an 18-month period involving five London, UK stroke services. Seventy-nine primary participants (30 PTs, 22 OTs, and 27 stroke survivors) were recruited to the study. Over 400 h of observation, 52 semi-structured interviews were conducted. Study data were analysed through thematic analysis. Key factors guiding therapist decision making were clinical expertise, professional role, stroke survivors' clinical presentation, therapist perspectives about stroke recovery, and clinical guidelines. Research evidence, stroke survivors' treatment preferences, organisational type, and pathway design were less influential factors. Therapy practice did not always address the physical needs of severely disabled stroke survivors. Multiple factors guided therapist decision making after severely disabling stroke. Alternative ways of therapist working should be considered to address the physical needs of severely disabled stroke survivors more fully. Multiple factors guide therapist decision making after severely disabling stroke, some of which result in the use of interventions that do not fully address stroke survivors' clinical needs. Therapists should critically reflect upon their personal beliefs and attitudes about severely disabling stroke to reduce potential sources of bias on decision making. Therapists should consider the timing and intensity of therapy delivery as well as their treatment approach to optimise outcomes after severely disabling stroke. [ABSTRACT FROM AUTHOR]