A comprehensive model of the psychology of environmental behaviour is proposed based on a meta-analysis of 56 data sets across various environmentally relevant behaviours. The model integrates the Theory of Planned Behaviour (TPB), Norm-Activation-Theory (NAT), and Value-Belief-Norm (VBN) theories, as well as habit strength. The model identifies intentions, perceived behavioural control, and habits as direct predictors of environmental behaviour. Intentions are influenced by attitudes, social norms, and perceived behavioural control. Personal norms, which are influenced by social norms, perceived behavioural control, awareness of consequences, ascription of responsibility, self-transcendence values, and self-enhancement values, play a mediating role in behaviour. Self-enhancement values negatively affect personal norms. The model also highlights the importance of de-habitualizing behaviour, strengthening social support, and increasing self-efficacy through concrete information about how to act. Value-based interventions have only an indirect effect. The model is supported by the data and shows that intentions are the strongest predictor of behaviour, followed by habit strength. Perceived behavioural control has a weaker impact. The model explains 36% of the variation in behaviour, with intentions explaining 55% of the variation in intentions and personal norms explaining 47% of the variation in personal norms. The model also shows that the strict causal chain from values to behaviour through NEP, awareness of consequences, and ascription of responsibility could not be confirmed. The results suggest that environmental behaviour is influenced by a complex interplay of factors, including moral motivations, personal norms, and habits. The model provides a general framework for understanding environmental behaviour and has implications for interventions aimed at changing behaviour. The findings highlight the importance of considering both proximal and distal variables in environmental behaviour research and interventions.A comprehensive model of the psychology of environmental behaviour is proposed based on a meta-analysis of 56 data sets across various environmentally relevant behaviours. The model integrates the Theory of Planned Behaviour (TPB), Norm-Activation-Theory (NAT), and Value-Belief-Norm (VBN) theories, as well as habit strength. The model identifies intentions, perceived behavioural control, and habits as direct predictors of environmental behaviour. Intentions are influenced by attitudes, social norms, and perceived behavioural control. Personal norms, which are influenced by social norms, perceived behavioural control, awareness of consequences, ascription of responsibility, self-transcendence values, and self-enhancement values, play a mediating role in behaviour. Self-enhancement values negatively affect personal norms. The model also highlights the importance of de-habitualizing behaviour, strengthening social support, and increasing self-efficacy through concrete information about how to act. Value-based interventions have only an indirect effect. The model is supported by the data and shows that intentions are the strongest predictor of behaviour, followed by habit strength. Perceived behavioural control has a weaker impact. The model explains 36% of the variation in behaviour, with intentions explaining 55% of the variation in intentions and personal norms explaining 47% of the variation in personal norms. The model also shows that the strict causal chain from values to behaviour through NEP, awareness of consequences, and ascription of responsibility could not be confirmed. The results suggest that environmental behaviour is influenced by a complex interplay of factors, including moral motivations, personal norms, and habits. The model provides a general framework for understanding environmental behaviour and has implications for interventions aimed at changing behaviour. The findings highlight the importance of considering both proximal and distal variables in environmental behaviour research and interventions.