The United States' trade and investment relationship with the countries of Europe is the largest and most complex in the world. U.S. transatlantic economic ties are dominated by relations with the 28-member European Union (EU).

The member states of the EU collectively represent a market of nearly 500 million consumers. Two-way U.S.-EU trade has been roughly balanced over time and the very high levels of foreign investment accounted for by each in the other's markets means that the transatlantic economy is arguably the most integrated on Earth.

Non-EU European countries (including the European Free Trade Area - EFTA - states of Switzerland, Norway, Iceland and Liechtenstein, and the countries of Southeast Europe and Turkey) also represent very significant markets for U.S. exporters and investors.