Background: Obesity is a global public health challenge, with increasing burden especially in emerging Asian economies. While the effectiveness of behavioural interventions for weight management has been extensively studied in the Western Hemisphere, it remains inadequately evaluated in Asian populations. Therefore, we performed a systematic review and meta-analysis to assess the efficacy of behavioural interventions in weight management in Asian adults living with overweight and obesity.Methods: We searched 6 databases and included randomized controlled trials (RCTs) published between 2008 to 2023 which compared behavioural interventions with usual care in Asian adults. We considered 3 adiposity indices: body weight, BMI and waist circumference. We i) conducted meta-analyses using random-effects models; ii) analysed the network of Behaviour Change Techniques (BCT) implemented and iii) performed stratified meta-regressions adjusting for 13 demographic and behavioural factors to identify factors associated with changes in adiposity.Results: Of 25,950 records screened, only 56 RCTs (0·22%, 11,191 participants) were conducted in Asia. The most frequently utilized BCT components were shaping knowledge (19·7%), feedback with monitoring (18·5%), and goals setting with planning (18·1%). Behavioural interventions promoted significant albeit modest improvement across adiposity indices, with reduced weight, BMI and waist circumferences (unadjusted: -2·12 Kg [-2·38; -1·85], -0·81 Kg/m2 [-0·93; -0·68] and -2·63 cm [-3·08; -2·18], respectively). In stratified meta-regressions, behavioural interventions incorporating both diet and physical activity show slightly higher adiposity loss (-3·03 Kg [-4·37; -1·69], -0·92 Kg/m2 [-1·34; -0·51] and -2·28 cm [-3·05; -1·5], respectively).Conclusions: Behavioural interventions in Asian adults living with overweight and obesity were associated with only modest (3-5%) improvements in adiposity. Greater success is linked to combined diet–exercise strategies, and targeted behaviour change techniques. Future research should prioritise culturally tailored, theory-driven interventions that can better meet the unique needs of Asian populations.