The inconsistency between pro-environmental attitudes and behaviour, known as the ‘attitude-behaviour’ gap, is not uncommon to ethical decision-making, however it’s exceptionally pronounced in scenarios associated with ‘green’ choice. Despite existing research offering numerous attempts to investigate the causes of the ‘attitude-behaviour’ gap in the pro-environmental domain, it is surprising that the major factors driving the ‘attitude-behaviour’ gap are still unknown. Therefore, we have grounded this study in Hunt-Vitell’s moral philosophy-based framework of ethical decision-making, which assumes morality as the central force impacting one’s behaviour and tested its effectiveness in predicting pro-environmental intentions vs. behaviours. The results from an online study of 612 MTurk participants from the US revealed that participants’ decision-making indeed depended on deontological and teleological framing of pro-environmental scenarios, and this in turn predicted the declining relationship between intention vs. behaviour. These findings suggest that morality is central to pro-environmental decision-making, and the ‘attitude-behaviour’ gap is the result of the disintegrated effects of moral dimension. For this reason, strengthening the impact of morality could be sufficient for aligning intentions with behaviours and thus closing the ‘attitude-behaviour’ gap.