Duchy of Racibórz (German: Herzogtum Ratibor, Czech: Ratibořské knížectví) was one of the duchies of Silesia. Its capital was Racibórz in Upper Silesia.

After Bolesław I the Tall and his younger brother Mieszko I Tanglefoot backed by Emperor Frederick I Barbarossa had retained their Silesian heritage in 1163, the Duchy of Racibórz was formed in 1172 as a territory for Mieszko. It was centered around the towns of Racibórz, Koźle and Cieszyn. Mieszko's small share was enlarged the first time in 1177, when he received the territories of Bytom, Oświęcim, Zator, Pszczyna and Siewierz from his uncle High Duke Casimir II the Just of Poland. In 1202 Mieszko occupied the Duchy of Opole of his deceased nephew Jarosław, forming the united Duchy of Opole and Racibórz.

After the death of Mieszko's grandson Duke Władysław Opolski in 1281, his sons again divided the Duchy of Opole and Racibórz and in 1290 the Duchy of Racibórz was recreated again, assigned to Władysław's youngest son Przemysław. Racibórz at that time comprised the lands of Wodzisław, Żory, Rybnik, Mikołów and Pszczyna, while some of the territory of was used for the creation of the duchies of Cziesyn and Bytom under Przemysław's brothers.

Racibórz [raˈt​͡ɕibuʂ] (German: Ratibor, Czech: Ratiboř) is a town in southern Poland with 60,218 inhabitants (2006) situated in the Silesian Voivodeship (since 1999), previously in Katowice Voivodeship (1975–1998). It is the capital of Racibórz County.

The name Racibórz is of Slavic origin and comes from the name of Duke Racibor, the city's founder.

Until the end of the 5th century AD, the lands of the later Racibórz settlement were inhabited by East Germanic Silinger tribes.

There is a possibility, that Racibórz was mentioned in a work of the "Bavarian Geographer" in 845 (this document mentions five strongholds of the Slavic Golensizi (Golenshitse, Holasici in Czech), a proto-Polish tribe, probably Racibórz was one of them). However, the first confirmed mention about Racibórz was made in 1108 in "Gesta principum Polonorum". It was the first historical capital of Upper Silesia. The Duchy of Racibórz was established by Duke Mieszko Plątonogi in 1172. The city was granted municipal privileges in 1217. From 1299 Racibórz was ruled by its own city council. The last duke of the Piast dynasty died in 1336 and from that time until 1521 the duchy and the city were ruled by the cadet branch of the Přemyslid dynasty. Racibórz was also ruled by the duke of Opole. The first coin with the Polish description "MILOST" was issued in Racibórz, in 1211 as well the first Polish national anthem "Gaude mater Polonia" which was written ca. 1260–70 in Latin by a brother from the Dominican monastery in Racibórz.