In this paper, efforts deployed by the EU to reform the police in Bosnia and Herzegovina and Ukraine, as part of a broader peacekeeping and peacebuilding strategy, are analysed from a critical and comparative perspective. It is argued that the EU was able to influence the policymaking process because of a positive conditionality policy and a favourable pro-reformist political context. This enabled the adoption of innovative police legislation consistent with the principles of democratic policing and EU standards. However, during its implementation, the police reform foundered in the conflictive internal political dynamics observable in both countries and due to the little leverage of the EU in such processes.