Behaviour change science is a central concept in Lifestyle Medicine. It focuses on modifying lifestyle risk factors through evidence-based interventions. The COM-B model provides a framework that considers Capability, Opportunity, and Motivation as key components influencing health behaviours. In clinical settings, understanding and modifying patient behaviours are crucial for better health outcomes. Identifying internal and external factors that influence behaviour is essential for effective intervention. Various approaches, such as education, persuasion, and enablement, are used to target different aspects of behaviour change. Behaviour Change Techniques (BCTs) play a vital role in creating specific strategies for behaviour modification. Contextual understanding recognises the importance of considering the patient’s environment and circumstances. Additionally, addressing health inequalities acknowledges the role of wider determinants of health and emphasises the need for interventions that do not exacerbate disparities. Using behaviour change science in the practice of Lifestyle Medicine enhances patient-centred care and health outcomes.