Great scientific effort has been devoted to understanding what drives pro-environmental behaviour, yet the question of the environmental attitude–behaviour gap remains unanswered. Studies have indicated that self-regulation and executive functions may reduce such a gap by increasing individuals’ ability to maintain attention on present actions and to resist goal-conflicting temptations. Given the inherent association of self-regulation and executive functions with dispositional mindfulness, we carried out a cross-sectional study to test the hypothesis of the role of dispositional mindfulness in explaining the phenomenon. Our results showed that higher levels of dispositional mindfulness, measured via the Five Facets Mindfulness Questionnaire (FFMQ), are related to a higher tendency to perform pro-environmental behaviour, and that the observing facet of the construct would predict higher pro-environmental behaviour scores. Interestingly, we also found the acting with awareness and nonjudging factors to be moderators of the relationship between pro-environmental attitudes and behaviours, suggesting that enhanced awareness of the present moment may favour higher congruence between attitudes and behaviours, and that higher acceptance may favour more adaptive coping strategies to the climate challenge. Our findings provide a novel contribution to the understanding of the relationship between mindfulness and pro-environmental behaviour and support the perspective that self-regulation skills would contribute to reducing the environmental attitude–behaviour gap.