Lviv Oblast (Ukrainian: Львівська область, romanized: Lvivska oblast, IPA: [ˈlʲwiu̯sʲkɐ ˈɔblɐsʲtʲ]), also referred to as Lvivshchyna (Ukrainian: Львівщина, IPA: [ˈlʲwiu̯ʃtʃɪnɐ]), is an oblast in western Ukraine. The administrative center of the oblast is the city of Lviv. The current population is 2,478,133 (2022 estimate).

The region is named after the city of Lviv which was founded by Daniel of Galicia, the King of Galicia, in the 13th century, where it became the capital of Galicia-Volhynia. Daniel named the city after his son, Leo. During this time, the general region around Lviv was known as Galicia–Volhynia, one of the strongest and most stable kingdoms in Eastern Europe of that time.

The oblast's strategic position at the heart of central Europe and as the gateway to the Carpathians has caused it to change hands many times over the centuries. In the Early Middle Ages, the territory was inhabited by the Lendians, an old Polish tribe. It was ruled variously by Great Moravia, Poland, Kievan Rus', the Kingdom of Galicia–Volhynia (circa 1200 to 1340; from 1246 under the suzerainty of the Golden Horde), and then ruled by the Kingdom of Poland and Polish–Lithuanian Commonwealth (1340 to 1772). Apart from the Polish and Ruthenian population, there were sizeable Scottish and Armenian communities in Lviv and Brody during Polish rule. Following the First Partition of Poland it passed to the Austro-Hungarian Empire (1772 to 1918), then the West Ukrainian People's Republic and Poland (1919 to 1939), when it was part of the Lwów Voivodeship of the Second Republic of Poland. The region's historically dominant Ukrainian population declared the area to be a part of an independent West Ukrainian People's Republic in November 1918 until June 1919, but this endured only briefly. Local autonomy was provided in international treaties but later on those were not honoured by the Polish government and the area experienced much ethnic tension between the Polish and Ukrainian populations.

The oblast was created as part of the Ukrainian Soviet Socialist Republic on 4 December 1939 following the Soviet invasion of eastern Poland and annexation of Eastern Galicia and Volhynia. Several NKVD prisoner massacres were committed in the area in 1941, including at Lviv, Sambir and Dobromyl.

It was occupied by Nazi Germany from 1941 to 1944 following the start of Operation Barbarossa, where most of the local Jewish population were killed. The Germans also established several prisoner-of-war camps with multiple forced labour subcamps in the region for Soviet, French and Belgian POWs, who were subjected to beatings, hunger, epidemics and executions, resulting in a high death rate. Following the end of World War II, the region remained in Soviet hands as was arranged in the Tehran and Yalta conferences. Most local Poles were expelled and Ukrainians expelled from Poland arrived.

As a result of the 1951 Polish–Soviet territorial exchange the area of Belz passed from Poland to the Lviv Oblast, whereas the area of Ustrzyki Dolne passed from the Drohobych Oblast to Poland. In 1959, Drohobych Oblast was incorporated into Lviv Oblast.

Given its historical development, Lviv Oblast is one of the least Russified and Sovietized parts of Ukraine, with much of its Polish and Habsburg heritage still visible today.

In Ukraine today, there are three provinces (oblasts) that formed the eastern part of the Kingdom of Galicia and Lodomeria. Two of these, Lviv Oblast and Ivano-Frankivsk Oblast were entirely contained in the kingdom; the third oblast of Ternopil was mainly in the kingdom apart from four of its most northerly counties (raions). The counties of the Kingdom of Galicia remained largely unchanged when they were incorporated into successor states; with minor changes as detailed below, the current counties are almost co-extensive with those of the Kingdom.