| Native Name: | Волинське князівство |
| Conventional Long Name: | Principality of Volhynia |
| Common Name: | Volhynia |
| Life Span: | 987–1199/1452 |
| Year Start: | 987 |
| Year End: | 1452 |
| Event End: | Incorporated into Lithuania |
| Event1: | United with Halych into Principality of Galicia-Volhynia |
| Date Event1: | 1199 |
| Event2: | War for succession between Poland and Lithuania |
| Date Event2: | 1340–1392 |
| P1: | Kievan Rus' |
| P2: | Yotvingia |
| S1: | Principality of Galicia–Volhynia |
| S2: | Grand Duchy of Lithuania |
| S3: | Kingdom of Poland (1385–1569)Kingdom of Poland |
| Image Map Caption: | Principality of Volhynia (shown in orange) |
| Coa Size: | 130px |
| Capital: | Volodymyr |
| Government Type: | Monarchy |
The Principality of Volhynia (Ukrainian: Волинське князівство) was a western Kievan Rus' principality founded by the Rurikid prince Vsevolod in 987 centered in the region of Volhynia, straddling the borders of modern-day Ukraine, Belarus, and Poland. From 1069 to 1118, it belonged to Izyaslavichi who primarily ruled from Turov (see Principality of Turov). After losing Turov to Monomakhovichi in 1105, the descendants of Iziaslav Yaroslavovich for a few years continued to rule in Volhynia. From 1154 to 1199, the Principality was referred to as the Principality of Volodymyr (Latin: Lodomeria) when the Principality of Lutsk (1154–1228) was separated.
The principality held the lands of the historic region of Volhynia from where it acquired its name. The capital of the principality as well as the largest and most important city of the region was Volodymyr. Other notable cities in the principality include Kremenets, Lutsk, Busk, Dorogobuzh, Brest, Belz, DuBetz and Shumsk.
The Principality of Volhynia along with her sister state, the Principality of Halych were formed by sons of the ruling Rurikid clan in Kiev. Following the fragmentation of Kievan Rus', the principality achieved autonomy in 1154.
Following the death of the prince of Halych Volodymyr Yaroslavovych in 1199, the Halych line of the Rurikid family had become extinct and the prince of Volhynia, Roman the Great annexed the principality, moved his seat to the city of Old Halych and formed the united Kingdom of Galicia-Volhynia.