<p>Sustainable behaviour necessitates a consumer’s consciousness of sustainability, an intention to act accordingly, and the resilience to stay on, and not get dissuaded along, the decision-making path. Yet evidence shows that consumers frequently fail to align their attitudes and intentions with corresponding behaviour, a phenomenon known as the ethical gap. To enhance understanding of the ethical gap, we synthesise and conceptualise empirical research findings through a systematic literature review of 110 articles. We identify recurring patterns and conceptual challenges, particularly concerning the scope and perspective of prior research. Most studies focus on purchase decisions, explore influencing factors rather than strategic interventions, assume rational decision-making, and primarily consider sustainability-oriented consumers. We challenge these assumptions and the resulting narrow view by conceptualising a process-oriented understanding of the ethical gap that unfolds across the different phases of the consumer decision-making process. We map influencing factors and intervention strategies across the decision-making process, allowing for a more dynamic and actionable understanding of the ethical gap. As such, we contribute to the sustainable behaviour literature by offering a phase-based integration of existing insights, identifying previously overlooked consumer segments and behavioural mechanisms, and proposing a structured research agenda to advance both theory and practice.</p>