Purpose - Multiple environmental behaviors will need to be adopted if climate change is to be addressed, yet current environmental decision-makingmodels explain the adoption of single behaviors only. The purpose of this paper is to address this issue by developing and evaluating a decision-making model that explains the co-adoption, or coaction, of multiple environmental behaviors. Design/methodology/approach - To test its cross-national utility, the model was assessed separately among online survey panel respondents from three countries: Australia (n=502), the UK (n=500), and the USA (n=501). In total, three environmental behaviors were examined: sourcing electricity from a green energy provider, purchasing green products, and public transport use. For each behavioral pair, participants were grouped according to whether they had enacted coaction (performed both behaviors), some action (performed either behavior), or no action (performed neither behavior). Findings - Irrespective of national sample and behavioral pair, those who engaged in coaction perceived greater personal benefits from reducing their CO2 emissions than those who enacted some action or no action. Moreover, perceived consumer effectiveness was typically greater among coaction participants than those in the no action group. Finally, perceived consumer effectiveness did not differ among those who had enacted coaction or some action. Originality/value - The current findings suggest that personal benefits and perceived consumer effectiveness are important motivational antecedents for the decision to engage in environmental coaction. International commercial or social marketing campaigns aimed at encouraging the adoption of multiple environmental behaviors should therefore seek to leverage these motivational factors.