The G20 or Group of 20 is an intergovernmental forum comprising 19 countries and the European Union (EU). It works to address major issues related to the global economy, such as international financial stability, climate change mitigation, and sustainable development.

The G20 is composed of most of the world's largest economies finance ministries, including both industrialised and developing nations; it accounts for around 80% of gross world product (GWP), 75% of international trade, two-thirds of the global population, and 60% of the world's land area.

The G20 was founded in 1999 in response to several world economic crises. Since 2008, it has convened at least once a year, with summits involving each member's head of government or state, finance minister, or foreign minister, and other high-ranking officials; the EU is represented by the European Commission and the European Central Bank. Other countries, international organizations, and nongovernmental organizations are invited to attend the summits, some on a permanent basis.

In its 2009 summit, the G20 declared itself the primary venue for international economic and financial cooperation. The group's stature has risen during the subsequent decade, and it is recognised by analysts as exercising considerable global influence; it is also criticised for its limited membership, lack of enforcement powers, and for the alleged undermining of existing international institutions. Summits are often met with protests, particularly by anti-globalization groups.