Ternopil Oblast' (Ukrainian: Тернопільська область, translit. Ternopil’s’ka oblast’; also referred to as Ternopilshchyna - Ukrainian: Тернопільщина) is an oblast' (province) of Ukraine. Its administrative center is Ternopil, through which flows the Seret River, a tributary of the Dnister.

The area of the oblast is 13,800 km². The Dnister forms the southern border with the Chernivtsi Oblast. Some of its tributaries flowing through the oblast are the Zbruch, the Seret and the Strypa Rivers. The Seret River, not to be confused with the Siret River nor the smaller Seret in Lviv Oblast, is a left tributary of the Dnister flowing through the oblast capital, i.e. Ternopil.

Before World War I, most of the current Ternopil oblast was part of Austro-Hungarian province Galicia. Only the northern-most section was within the borders of Russia. From 1918 until World War II, the area formed the Tarnopol Voivodeship in the newly independent country of Poland. As was common throughout the western Ukraine, the non-Ukrainian population was concentrated in the cities. Before World War II, the population of Ternopil was 40% Polish, 20% Ukrainian, and 40% Jewish. The oblast is sometimes associated with the Ukrainian nationalist movement, as during the Polish-Ukrainian War, Ukrainian nationalist forces launched the Chortkiv offensive to stop Polish attempts to topple the newly established West Ukrainian People's Republic. Later the local ethnically Ukrainian population was loyal to the revolutionary UPA.

Ternopil (Ukrainian: Тернопіль, translit. Ternopil’, Polish: Tarnopol, German: Tarnopol Russian: Тернополь, translit. Ternopol’), is a city in western Ukraine, located on the banks of the Seret River. Ternopil is one of the major cities of Western Ukraine and the historical region of Galicia. It is served by Ternopil Airport.

In 2010, the population was 218,641.

The city is the administrative center of the Ternopil Oblast (province), as well of the surrounding Ternopil Raion (district) within the oblast. However, Ternopil is a city of oblast subordinance, thus being subject directly to the oblast authorities rather to the raion administration housed in the city itself.

The city was founded in 1540 by Jan Amor Tarnowski as a Polish military stronghold and a castle. In 1544 the Ternopil Castle was constructed and repelled its first Tatar attacks. In 1548 Ternopil was granted city rights by king Sigismund I of Poland. In 1567 the city passed to the Ostrogski family. In 1575 it was plundered by Tatars. In 1623 the city passed to the Zamoyski family.