Galicia (/ɡəˈlɪʃ(i)ə/ gə-LISH-(ee-)ə; also known by the variant name Galizia; Polish: Galicja, IPA: [ɡaˈlit͡sja] ^ⓘ; Ukrainian: Галичина, romanized: Halychyna, IPA: [ɦɐlɪtʃɪˈnɑ]; Yiddish: גאַליציע, romanized: Galitsye; see below) is a historical and geographic region spanning what is now southeastern Poland and western Ukraine, long part of the Polish–Lithuanian Commonwealth. It covers much of the other historic regions of Red Ruthenia (centered on Lviv) and Lesser Poland (centered on Kraków).

The name of the region derives from the medieval city of Halych, and was first mentioned in Hungarian historical chronicles in the year 1206 as Galiciæ. The eastern part of the region was controlled by the medieval Kingdom of Galicia–Volhynia before it was annexed by the Kingdom of Poland in 1352 and became part of the Ruthenian Voivodeship. During the partitions of Poland, it was incorporated into a crown land of the Austrian Empire — the Kingdom of Galicia and Lodomeria.

The nucleus of historic Galicia lies within the modern regions of western Ukraine: the Lviv, Ternopil, and Ivano-Frankivsk oblasts near Halych. In the 18th century, territories that later became part of the modern Polish regions of the Lesser Poland Voivodeship, Subcarpathian Voivodeship, and Silesian Voivodeship were added to Galicia after the collapse of the Polish–Lithuanian Commonwealth.

Eastern Galicia became contested ground between Poland and Ruthenia in medieval times and was fought over by Austria-Hungary and Russia during World War I and also fight over by Poland and Ukraine later in the 20th century. In the 10th century, several cities were founded there, such as Volodymyr and Jaroslaw, whose names mark their connections with the Grand Princes of Kiev, Vladimir the Great and Yaroslav the Wise. There is considerable overlap between Galicia and Podolia (to the east) as well as between Galicia and southwest Ruthenia, especially in a cross-border region (centred on Carpathian Ruthenia) inhabited by various nationalities and religious groups.

The name of the region in the local languages is:

Some historians speculated that the name had to do with a group of people of Thracian origin (i.e. Getae) who during the Iron Age moved into the area after the Roman conquest of Dacia in 106 CE and may have formed the Lypytsia culture with the Venedi people who moved into the region at the end of La Tène period. The Lypytsia culture supposedly replaced the existing Thracian Hallstatt (see Thraco-Cimmerian) and Vysotske cultures. Some other scholars assert that the name Halych has Slavic origins – from halytsa, meaning "a naked (unwooded) hill", or from halka which means "jackdaw". (The jackdaw featured as a charge in the city's coat of arms and later also in the coat of arms of Galicia-Lodomeria. The name, however, predates the coat of arms, which may represent canting or simply folk etymology). Although Ruthenians drove out the Hungarians from Halych-Volhynia by 1221, Hungarian kings continued to add Galicia et Lodomeria to their official titles.

In 1349, in the course of the Galicia–Volhynia Wars, King Casimir III the Great of Poland conquered the major part of Galicia and put an end to the independence of this territory. Upon the conquest Casimir adopted the following title:

Casimir by the grace of God king of Poland and Rus (Ruthenia), lord and heir of the land of Kraków, Sandomierz, Sieradz, Łęczyca, Kuyavia, Pomerania (Pomerelia). Latin: Kazimirus, Dei gratia rex Polonie et Rusie, nec non-Cracovie, Sandomirie, Siradie, Lancicie, Cuiavie, et Pomeranieque Terrarum et Ducatuum Dominus et Heres.