The Making Every Contact Count MECC programme encourages staff to have opportunistic brief behaviour change conversations with service users. It uses the day-to-day interactions that healthcare professionals, or those within other organisations, including the not-for-profit sector have with people, to support them in making positive changes to their physical and mental health, and wellbeing. The aim of this review is to assess which elements or types of MECC training, or comparable interventions, are most effective and preferred by those who would implement MECC in practice. The review included evidence available up until June 2024. 11 studies were included. These all focused on healthcare organisations and included health care or public health professionals, with two also including trainees who worked in a local authority. There was consistent evidence that training increased both trainee confidence and use of MECCrelated techniques immediately following training. There was some evidence that despite a slight reduction, these improvements were at least maintained up to one year later. There was no evidence on the longer-term effect, other than an indication that refresher training would be appreciated. There was also no evidence assessing whether improvements in trainee confidence and competence had any impact on service user behaviour change and outcomes. There was an indication that face-to-face training was preferred to online training. Barriers to MECC training attendance included a feeling that there was not enough time, and a lack of managerial support. Barriers to MECC utilisation included a feeling that there was not enough time, a lack of organisational and managerial support, a fear of upsetting patients, and a lack of awareness of downstream support services to refer service users to following healthy behaviour conversations. The evidence indicated that barriers to MECC training and utilisation could be overcome via provision of information about downstream support services, and improved organisational and managerial support for both attendance at MECC training and its use in practice. Further research is needed. This should include research into the impact from MECC on patient behaviour and eventual outcomes, and how these change following training.