DESIGN: People living with HIV/AIDS (PLHIV) are at increased risk of diarrhoeal disease and enteric infection. This review assesses the effectiveness of water, sanitation, and hygiene (WASH) interventions to prevent disease among PLHIV. METHODS: We searched MEDLINE, EMBASE, Global Health, The Cochrane Library, Web of Science, LILACS, Africa-wide, IMEMR, IMSEAR, WPRIM, CNKI, and WanFang. We also hand searched conference proceedings, contacted researchers and organizations, and checked references from identified studies. Eligible studies were those involving WASH interventions among PLHIV that reported on health outcomes and employed a controlled study design. We extracted data, explored heterogeneity, sub-grouped based on outcomes, calculated pooled effects on diarrhoeal disease using meta-analysis, and assessed studies for methodological quality. RESULTS: Ten studies met the eligibility criteria and are included in the review, of which nine involved water quality interventions and one involved promotion of handwashing. Among eight studies that reported on diarrhoea, water quality interventions (seven studies, pooled RR = 0.57, 95% CI: 0.38-0.86) and the handwashing intervention (one study, RR = 0.42, 95% CI: 0.33-0.54) were protective against diarrhoea. One study reported that household water treatment combined with insecticide treated bednets slowed the progression of HIV/AIDS. The validity of most studies is potentially compromised by methodological shortcomings. CONCLUSION: No studies assessed the impact of improved water supply or sanitation, the most fundamental of WASH interventions. Despite some evidence that water quality interventions and handwashing are protective against diarrhoea, substantial heterogeneity and the potential for bias raise questions about the actual level of protection.