With the ageing of the world's population comes significant implications for nearly all sectors of society, including health and aged care spending. Health and aged care systems need to respond to the increasing need for services for older people. Occupational therapy is concerned with maintaining a person's functional independence and well‐being from preventative and treatment perspectives. The aim of this systematic review was to identify the costs and outcomes of occupational therapy for people with cognitive and/or functional decline. The searches for this review were conducted on 23 September 2016 and updated on 20 April 2017. Full economic evaluation studies, partial economic evaluations, randomised trials reporting estimates of resource use or costs associated with intervention(s) and comparator(s) and studies with pre‐ and post‐intervention cost comparators were included. Thirteen studies met the inclusion criteria. The type and duration of occupational therapy intervention in the included studies varied, ranging from one‐off assessments through to systematic multicomponent programmes. Results suggested that structured occupational therapy interventions which comprised of multiple consultations and engaged caregivers delivered better functional and economic outcomes.