Mandates of United Nations (UN) peacekeeping missions increasingly include stabilisation and peace enforcement components, which imply a proactive use of force often carried out by national, regional or multinational non-UN partners, operating either in support of or with the support of the UN, acting as 'proxies'. This article analyses the legal, policy and perception/security implications of different types of 'peace operations by proxy' and the additional challenges that such operations create for humanitarian action. It suggests some mitigating measures, including opportunities offered by the UN Human Rights Due Diligence Policy, for a more coherent approach to the protection of civilians, but also acknowledges some of the limitations to an independent UN-led humanitarian action.