This study explores how internal governance mechanisms influence greenwashing behaviours in comparison between family businesses and non-family businesses. Drawing on multiple theories including agency, legitimacy, socioemotional wealth and faultlines concepts, we employ top-listed family businesses and propensity score matched non-family businesses worldwide. The results reveal a U-shaped association, with family businesses showing greater responsiveness than non-family businesses. This study further investigates several mechanisms, including exogenous events, legal contexts, socio-linguistic determinants, and SEW endorsement. Our findings indicate that the effect of internal governance mechanisms on greenwashing is not always linear; rather, there is a turning point, highlighting the nuances of corporate governance mechanisms on greenwashing behaviour, which provide a theoretical contribution and practical implications.