Background and aims: Alcohol use by pregnant and parenting women can have serious and long-lasting consequences for both the mother and offspring. We reviewed the evidence for psychosocial interventions to reduce maternal drinking. Design: Literature searches of PsycINFO, PubMed and Scopus identified randomised controlled trials of interventions with an aim of reduced drinking or abstinence in mothers or pregnant women. Setting: Interventions were delivered in healthcare settings and homes. Participants: Pregnant women and mothers with dependent children. Interventions: Psychosocial interventions were compared with usual care or no intervention. Measurements: The revised Cochrane risk-of-bias tool for randomised trials was used for quality assessments. Narrative synthesis summarised the findings of the studies with a subset of trials eligible for random-effects meta-analysis. General and alcohol-specific behaviour change techniques (BCTs) were identified to investigate potential mechanism of change. Results: Twenty-four studies were included (20 pregnancy, four motherhood). Because of quality of reporting, data from only six pregnancy and four motherhood studies could be pooled. A significant treatment effect was revealed by the meta-analyses of pregnancy studies regarding abstinence (OR = 2.31, 95% CI = 1.61, 3.32; P < 0.001) and motherhood studies regarding a reduction in drinking (standardised mean difference [SMD] = -0.20, 95% CI = -0.38, -0.02; P = 0.03). Narrative synthesis of the remaining trials yielded inconsistent results regarding intervention effectiveness. A wide range of BCTs were used, present in both effective and ineffective interventions. The most commonly used general and alcohol-specific BCTs included information about consequences, social support, goal setting and action planning. Conclusions: In pregnant women identified as consuming alcohol, psychosocial interventions appear to increase abstinence rates compared with usual care or no intervention. Similarly, such interventions appear to lead to a reduction in alcohol consumption in mothers with dependent children. It is unclear that behaviour change techniques are contributing to these effects. Conclusions from randomised controlled trials are only meaningful if the behavioural outcome, population, setting, intervention and comparator are clearly reported. An important barrier when it comes to identifying effective behaviour change techniques is a widespread failure to provide enough information in study reports.