Multilateral organisations, such as United Nations bodies, are mandated to address crucial global challenges, ranging from climate change, peacekeeping and security to relations between states, sustainable development and the protection of human rights. To fulfil these ambitious missions, they are allocated substantial volumes of money, including by bilateral donor agencies from OECD-DAC states. These two factors – central political importance and large budgets – mean that it is vital for citizens around the world that multilateral organisations have robust internal governance mechanisms in place. Strong checks and balances are required to prevent corruption and other forms of misconduct by staff from undermining these organisations’ ability to protect people, the planet and prosperity. Since there is no “one size fits all” integrity management system that would cater to the existing variety of multilaterals, this paper highlights key integrity functions at a level high enough that it can be subsumed into anti-corruption programming. The key integrity functions include: a) prevention; b) detection; c) investigation; d) sanctions; and e) disclosure.