The Treaties of Tilsit were two agreements signed by Napoleon I of France in the town of Tilsit in July 1807 in the aftermath of his victory at Friedland. The first was signed on 7 July, between Emperor Alexander I of Russia and Napoleon I of France, when they met on a raft in the middle of the Neman River. The second was signed with Prussia on 9 July. The treaties were made at the expense of the Prussian king, who had already agreed to a truce on 25 June after the Grande Armée had captured Berlin and pursued him to the easternmost frontier of his realm. In Tilsit, he ceded about half of his pre-war territories.From those territories, Napoleon had created French sister republics, which were formalized and recognized at Tilsit: the Kingdom of Westphalia, the Duchy of Warsaw and the Free City of Danzig; the other ceded territories were awarded to existing French client states and to Russia.

Napoleon not only cemented his control of Central Europe but also had Russia and the truncated Prussia ally with him against his two remaining enemies, the United Kingdom and Sweden, triggering the Anglo-Russian and Finnish War. Tilsit also freed French forces for the Peninsular War. Central Europe became a battlefield again in 1809 when Austria and the UK engaged France in the War of the Fifth Coalition. Following the end of the Napoleonic Wars in 1815, the Congress of Vienna would restore many Prussian territories.

By signing these treaties, France left Iran and the Ottomans, who had previously hoped for France's help under treaties with France (including Finnstein), in the face of Russian aggression, and established the loss of parts of Iran in the Caucasus, such as the present-day republic. Azerbaijan, Georgia and Armenia.