摘要:This Campbell Systematic Review examines the effectiveness of different approaches for promoting handwashing and sanitation behaviour change, and factors affecting implementation, in low and middle‐income countries. The review summarises evidence from 42 impact evaluations, and from 28 qualitative studies. Community‐based approaches which include a sanitation component can increase handwashing with soap at key times; use of latrines and safe disposal of faeces; and reduce the frequency of open defecation. Social marketing seems less effective. The approach mainly shows an effect on sanitation outcomes when interventions combine handwashing and sanitation components. Sanitation and hygiene messaging with a focus on handwashing with soap has an effect after the intervention has ended, but there is little impact on sanitation outcomes. However, these effects are not sustainable in the long term. Using elements of psychosocial theory in a small‐scale handwashing promotion intervention, or adding theory‐based elements such as infrastructure promotion or public commitment to an existing promotional approach, seem promising for handwashing with soap. None of the approaches described have consistent effects on behavioural factors such as knowledge, skills and attitude. There are no consistent effects on health.