Abstract Objective/Aims: To determine the barriers and enablers to behavioural change to reduce free sugar intake related to dental caries in a sample of UK adults who identify their ethnicity as White. Materials and methods: Qualitative study comprising semi-structured interviews of 27 participants. Interviews were recorded, transcribed and analysed using thematic analysis methods. The Capability-Opportunity-Motivation-Behaviour model (COM-B) and the Theoretical Domains Framework (TDF) were used to guide the derivation of themes. Results: Data saturation occurred at 27 interviews. The COM-B Model and TDF domains captured various factors that may influence the consumption of free sugar. TDF elements which are reflected in the study are: Knowledge; Psychological skills; Memory, attention, and decision processes; Behavioural regulation; Physical skills; Social influence; Environmental context and resources; Social and professional role and identity; Beliefs about capabilities; Beliefs about consequence; Intentions and goals reinforcement; and Emotions. COM-B Model elements which are reflected in the study are: psychological capabilities, physical capabilities, social opportunities, physical opportunities, reflective motivation, and automatic motivation. Discussion and conclusion: The COM-B model and TDF framework provided a comprehensive account of the barriers and facilitators of reducing sugar intake among white ethnic groups.