The Group of 7 (G7) comprises some of the largest donors to the United Nations (UN). This is why the G7 is uniquely positioned to address challenges stemming from a UN revenue profile that heavily relies on unpredictable forms of voluntary finance. If the G7 is serious about wanting a more effective UN system for managing an expanding list of global threats – in line with the programme of the German G7 presidency – individual UN entities must be solidly financed to ensure their independent capacity to act. The need to strengthen the UN has become even more urgent with Russia’s war against Ukraine that represents a major challenge to the legitimacy and effectiveness of a rules-based international order. With regard to UN funding, the G7 should work towards (1) raising assessed contributions across the UN system, starting with the World Health Organisation; (2) tweaking the formula used to calculate each member state’s share of assessed contributions to give due consideration to evolving global challenges; (3) ensuring that the formula is fit for delivering on the global functions of the UN; and (4) reinforcing mechanisms for penalising arrears. Such financing reforms would strengthen the UN’s role as a foundational global public good through which transnational challenges can be tackled.