PURPOSE:To evaluate the effect of behavioural interventions on levels of physical activity after hip or knee joint replacement. MATERIALS AND METHODS:A systematic review with meta-analysis of randomised controlled trials to determine the effectiveness of behavioural interventions to increase physical activity levels after hip or knee joint replacement. Six databases were searched. Standardised mean differences (SMD) were calculated. The GRADE approach was used to evaluate the level of evidence of each meta-analysis. RESULTS:From a yield of five trials, physical activity was quantified as active minutes per day, daily energy expenditure and daily steps. There was low to moderate-quality evidence from three meta-analyses with observed positive effects that could not conclude whether behavioural interventions increased physical activity in active minutes per day (SMD = 0.18, 95% CI -0.14, 0.51), daily energy expenditure (SMD = 0.31, 95% CI -0.24, 0.87) or daily steps (MD = 844.7, 95% CI -178.6, 1,868.0). CONCLUSIONS:The effectiveness of behavioural interventions to address the low levels of physical activity levels observed after hip or knee joint replacement remains uncertain. Implications for rehabilitation Physical activity levels after hip or knee joint replacements fail to meet recommended daily activity guidelines, increasing the associated risk of cardiovascular disease and early mortality. Rehabilitation interventions that target behaviour change may have an impact in increasing physical activity levels after hip or knee joint replacement surgery. The optimal type and timing of behavioural interventions to effectively increase physical activity levels in this cohort remains unclear. Rehabilitation professionals are advised to highlight the benefits of meeting physical activity recommendations (150 min of moderate-intensity aerobic physical activity or 75 min of vigorous-intensity aerobic physical activity per week) to people who have undergone hip or knee joint replacement, and that behavioural intervention may support patients to meet these recommendations.