Global warming will lead to more frequent and intense heatwaves across all regions of the world in the coming decades. Adaptation at the individual level plays a key role in helping populations cope with these extreme events. This study undertakes a systematic review of the academic literature on the determinants of heat-adaptive behaviours (HABs) following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. A Boolean algorithm was used on two online databases (PubMed and Web of Science Core Collection) to retrieve 73 relevant, quantitative, peer-reviewed papers. All included studies focus on high-income economies (N = 48) or middle-income economies (MIEs, N = 25). A meta-analysis was performed on 34 studies using a random-effects model, with an emphasis on heat-related perceptions (perceived efficacy, risk and threat) and heat-related knowledge (HRK), as these variables are the most likely levers of behavioural change. Perceived efficacy, HRK, perceived threat and gender (i.e. being female) are positively associated with the adoption of HABs. A moderation analysis reveals heterogeneity in the effect of these variables by country income group, with low HRK and perceived threat constituting stronger barriers to HABs in MIEs. This study also highlights various gaps in the current literature, regarding the populations studied, the statistical methods used, and the lack of standardization of HABs and perception concepts.Read less <