Objective: To determine the effects of tilt-in-space seating on outcomes for people with neurological or neuromuscular impairment who cannot walk. Data sources: Search through electronic databases (MEDLINE, Embase, CINAHL, AMED). Discussions with researchers who are active in field. Review methods: Selection criteria included interventional studies that investigated the effects of seat tilt on outcome or observational studies that identified outcomes for those who had used tilt-in-space seating in populations with neurological or neuromuscular impairments. Two reviewers independently selected trials for inclusion, assessed quality and extracted data. Results: Nineteen studies were identified which fulfilled the selection criteria. Seventeen of these were essentially before—after studies investigating the immediate effects of tilting the seating. All studies looked at populations with neurological impairment, and most were on children with cerebral palsy (n = 8) or adults with spinal cord injury (n = 8). Reviewer's conclusion: Posterior tilt can reduce pressures at the interface under the pelvis.