Alexander I (Russian: Алекса́ндр I Па́влович, tr. Aleksándr I Pávlovich, IPA: [ɐlʲɪkˈsandr ˈpavɫəvʲɪt͡ɕ]; 23 December [O.S. 12 December] 1777 – 1 December [O.S. 19 November] 1825) was Emperor of Russia from 1801, the first King of Congress Poland from 1815, and the Grand Duke of Finland from 1809 to his death. He was the eldest son of Emperor Paul I and Sophie Dorothea of Württemberg.

The son of Grand Duke Paul Petrovich, later Paul I, Alexander succeeded to the throne after his father was murdered. He ruled Russia during the chaotic period of the Napoleonic Wars. As prince and during the early years of his reign, Alexander often used liberal rhetoric, but continued Russia's absolutist policies in practice. In the first years of his reign, he initiated some minor social reforms and (in 1803–04) major liberal educational reforms, such as building more universities. Alexander appointed Mikhail Speransky, the son of a village priest, as one of his closest advisors. The Collegia were abolished and replaced by the State Council, which was created to improve legislation. Plans were also made to set up a parliament and sign a constitution.

In foreign policy, he changed Russia's position towards France four times between 1804 and 1812 among neutrality, opposition, and alliance. In 1805 he joined Britain in the War of the Third Coalition against Napoleon, but after suffering massive defeats at the battles of Austerlitz and Friedland, he switched sides and formed an alliance with Napoleon by the Treaty of Tilsit (1807) and joined Napoleon's Continental System. He fought a small-scale naval war against Britain between 1807 and 1812 as well as a short war against Sweden (1808–09) after Sweden's refusal to join the Continental System. Alexander and Napoleon hardly agreed, especially regarding Poland, and the alliance collapsed by 1810. Alexander's greatest triumph came in 1812 when Napoleon's invasion of Russia proved to be a catastrophic disaster for the French. As part of the winning coalition against Napoleon, he gained territory in Finland and Poland. He formed the Holy Alliance to suppress revolutionary movements in Europe which he saw as immoral threats to legitimate Christian monarchs. He also helped Austria's Klemens von Metternich in suppressing all national and liberal movements.

During the second half of his reign, Alexander became increasingly arbitrary, reactionary, and fearful of plots against him; as a result he ended many of the reforms he made earlier. He purged schools of foreign teachers, as education became more religiously driven as well as politically conservative. Speransky was replaced as advisor with the strict artillery inspector Aleksey Arakcheyev, who oversaw the creation of military settlements. Alexander died of typhus in December 1825 while on a trip to southern Russia. He left no legitimate children, as his two daughters died in childhood. Neither of his brothers wanted to become emperor. After a period of great confusion (that presaged the failed Decembrist revolt of liberal army officers in the weeks after his death), he was succeeded by his younger brother, Nicholas I.