Police reform is widely undertaken in developing and post-authoritarian countries. The starting point for analysis of this phenomenon, it is suggested, is the absence of public trust in police that characterizes police–community relations in these countries. Without public trust in police, ‘policing by consent’ is difficult or impossible and public safety suffers. The nature of trust is examined in general terms and related to the problem of trust in governance. Then, the problematic nature of trust of the police is considered; structural features as well as performance aspects are invoked to explain distrust of police. In the penultimate section, the question of how to build trustworthy police forces is examined in the light of what has been learnt about the difficulties of maintaining or establishing trust in police. Process as well as substantive improvements each play a role here. In addition to building trust, ways of institutionalizing distrust are needed. The article concludes by pointing to some inherent limits or constraints upon trust-building, including the impact of the wider environment in which policing occurs, and the need to trust the tools we use for building trust.