BACKGROUND: Evidence supports the use of pricing interventions in achieving healthier behaviour at population level. The public acceptability of this strategy continues to be debated throughout Europe, Australasia and USA. We examined public attitudes towards, and beliefs about the acceptability of pricing policies to change health-related behaviours in the UK. The study explores what underlies ideas of acceptability, and in particular those values and beliefs that potentially compete with the evidence presented by policy-makers. METHODS: Twelve focus group discussions were held in the London area using a common protocol with visual and textual stimuli. Over 300,000 words of verbatim transcript were inductively coded and analyzed, and themes extracted using a constant comparative method. RESULTS: Attitudes towards pricing policies to change three behaviours (smoking, and excessive consumption of alcohol and food) to improve health outcomes, were unfavourable and acceptability was low. Three sets of beliefs appeared to underpin these attitudes: (i) pricing makes no difference to behaviour; (ii) government raises prices to generate income, not to achieve healthier behaviour and (iii) government is not trustworthy. These beliefs were evident in discussions of all types of health-related behaviour. CONCLUSIONS: The low acceptability of pricing interventions to achieve healthier behaviours in populations was linked among these responders to a set of beliefs indicating low trust in government. Acceptability might be increased if evidence regarding effectiveness came from trusted sources seen as independent of government and was supported by public involvement and hypothecated taxation.