Citizens’ perception of fairness, in process as much as in outcome, is a critical dimension of trust. People must feel they have a real voice, be treated with respect, and receive necessary explanations. Positive perceptions of fairness lead to greater acceptance of agency decisions, better compliance with regulations, and more co-operative behaviour in dealing with agents of the government. The reverse also holds: citizens are more likely to accept negative outcomes, such as financial penalties, if they feel that they have been treated fairly. In general terms, low trust generates extra transaction costs for citizens, businesses and government. This chapter looks at empirical evidence on the links between good regulatory practice and trust in public policy.