Objective: The Common Risk Factor Approach proposes that public health efforts can be improved by multiple agencies working together on a shared risk factor. The present study aimed to assess the acceptability to parents, dental practice staff and commissioners of the delivery of dietary advice in the dentistry setting in order to address obesity. Design: Semi-structured focus groups with dental practice staff and one-to-one interviews with parents of pre-school children and public health commissioners involved in an oral health promotion initiative delivering dietary advice in dental surgeries. Data were analysed using the Framework Approach. Setting: General dental practice surgeries and pre-schools in areas of high deprivation in north-east England. Subjects: Parents (n 4), dental practice staff (n 23) and one commissioner. Results: All participants found acceptable the concept of delivering public health messages in non-conventional settings. Dental practice staff were concerned about the potential for conflicting messages and deprioritisation of oral health advice, and they identified practical barriers to delivery, such as lack of training. Parents were very apprehensive about the potential of such approaches to stigmatise overweight children, including bullying. Uncertainty over the causes of obesity led to confusion about its solutions and the roles of public health and health care. Conclusions: Major concerns about the implementation of the Common Risk Factor Approach were raised by parents and dental practice staff. Specific dietary guidance for both oral health and healthy weight, as well as further research into issues of suitability, feasibility and stigmatisation, are needed.