The 1748 Treaty of Aix-la-Chapelle, sometimes called the Treaty of Aachen, ended the War of the Austrian Succession, following a congress assembled on 24 April 1748 at the Free Imperial City of Aachen.

The two main protagonists in the war, Britain and France, opened peace talks in the Dutch city of Breda in 1746. Agreement was delayed by British hopes of improving their position; when this failed to occur, a draft treaty was agreed on 30 April 1748. A final version was signed on 18 October 1748 by Britain, France, and the Dutch Republic.

The terms were then presented to the other belligerents, who could either accept them, or continue the war on their own. Austria, Spain, and Sardinia had little choice but to comply, and signed separately. The Modena, and Genoa joined together on 21 January 1749.

The treaty largely failed to resolve the issues that caused the war, while most of the signatories were unhappy with the terms. Maria Theresa resented Austria's exclusion from the talks, and blamed Britain for forcing her to accept concessions, while British politicians felt they had received little benefit for the financial subsidies paid to her. The combination of factors led to the strategic realignment known as the Diplomatic Revolution, and the outbreak of the Seven Years' War in 1756.