In international relations, international order consists of patterned or structured relationships (such as polarity) between actors on the international level.

David Lake, Lisa Martin and Thomas Risse define "order" as "patterned or structured relationships among units".

Michael Barnett defines an international order as "patterns of relating and acting" derived from and maintained by rules, institutions, law and norms. International orders have both a material and social component. Legitimacy (the generalized perception that actions are desirable, proper or appropriate) is essential to political orders. George Lawson has defined an international order as "regularized practices of exchange among discrete political units that recognize each other to be independent." John Mearsheimer defines an international order "an organized group of international institutions that help govern the interactions among the member states."

In After Victory (2001), John Ikenberry defines a political order as "the governing arrangements among a group of states, including its fundamental rules, principles and institutions."

The United Nations has been characterized as a proxy for how states broadly perceive the international order.

Jeff Colgan has characterized international order as entailing multiple subsystems. These subsystems can experience drastic change without fundamentally changing the international order.

The liberal international order is a set of global, rule-based, structured relationships based on political liberalism, economic liberalism and liberal internationalism since the late 1940s. More specifically, it entails international cooperation through multilateral institutions (like the United Nations, World Trade Organization and International Monetary Fund) and is constituted by human equality (freedom, rule of law and human rights), open markets, security cooperation, promotion of liberal democracy, and monetary cooperation. The order was established in the aftermath of World War II, led in large part by the United States.

The nature of the liberal international order, as well as its very existence, has been debated by scholars. The LIO has been credited with expanding free trade, increasing capital mobility, spreading democracy, promoting human rights, and collectively defending the West from the Soviet Union. The LIO facilitated unprecedented cooperation among the states of North America, Western Europe and Japan. Over time, the LIO facilitated the spread of economic liberalism to the rest of the world, as well as helped consolidate democracy in formerly fascist or communist countries.