Saxony, officially the Free State of Saxony, is a landlocked state of Germany, bordering the states of Brandenburg, Saxony-Anhalt, Thuringia, and Bavaria, as well as the countries of Poland and the Czech Republic. Its capital is Dresden, and its largest city is Leipzig. Saxony is the tenth largest of Germany's sixteen states, with an area of 18,413 square kilometres (7,109 sq mi), and the seventh most populous, with more than 4 million inhabitants.

The term Saxony has been in use for more than a millennium. It was used for the medieval Duchy of Saxony, the Electorate of Saxony of the Holy Roman Empire, the Kingdom of Saxony, and twice for a republic. The first Free State of Saxony was established in 1918 as a constituent state of the Weimar Republic. After World War II, it was under Soviet occupation before it became part of communist East Germany and was abolished by the government in 1952. Following German reunification, the Free State of Saxony was reconstituted with enlarged borders in 1990 and became one of the five new states of the Federal Republic of Germany.

The area of the modern state of Saxony should not be confused with Old Saxony, the area inhabited by Saxons. Old Saxony corresponds roughly to the modern German states of Lower Saxony, Saxony-Anhalt, and the Westphalian portion of North Rhine-Westphalia. Historically the region of Saxony has sometimes been referred to as Upper Saxony or Obersachsen in German to distinguish it from Lower Saxony.

The state is also home to a minority of Sorbs, a West Slavic ethnic group native to the area, numbering an estimated 80,000 people.

Saxony has a long history as a duchy, an electorate of the Holy Roman Empire (the Electorate of Saxony), and finally as a kingdom (the Kingdom of Saxony). In 1918, after Germany's defeat in World War I, its monarchy was overthrown and a republican form of government was established under the current name. The state was broken up into smaller units during communist rule (1949–1989), but was re-established on 3 October 1990 on the reunification of East and West Germany.

In prehistoric times, the territory of present-day Saxony was the site of some of the largest of the ancient central European monumental temples, dating from the fifth millennium BC. Notable archaeological sites have been discovered in Dresden and the villages of Eythra and Zwenkau near Leipzig. The Germanic presence in the territory of today's Saxony is thought to have begun in the first century BC.

Parts of Saxony were possibly under the control of the Germanic King Marobod during the Roman empire era. By the late Roman period, several tribes known as the Saxons emerged, from which the subsequent state(s) draw their name.

Since the late 6th century, the territory of modern-day Saxony and parts of Thuringia was populated by Polabian Slavs, most prominently the Sorbs. It was conquered by Francia and subsequently organized as the Sorbian March. A legacy of this period is the modern ethnic group of Sorbs in Saxony. Eastern and western parts of present Saxony were ruled by Bohemia at various times between 1075 and 1635 (with some intermissions), and Schirgiswalde (Upper Sorbian: Šěrachów; Czech: Šerachov) remained a Bohemian exclave until 1809. Eastern parts were also ruled by Poland between 1002 and 1032, by the Duchy of Jawor, the southwesternmost duchy of fragmented Piast-ruled Poland, from 1319 to 1346, and by Hungary from 1469 to 1490, and Pechern (Upper Sorbian: Pěchč) was part of the Duchy of Żagań, one of the Lower Silesian duchies formed in the course of the medieval fragmentation of Poland, remaining under the Piast dynasty until 1472.