| Native Name: | |
| Conventional Long Name: | Duchy of Poznań |
| Era: | High Middle Ages |
| Status: | Fiefdom within the Duchy of Poland (1177–1227) Independent state (1227–1279) |
| Government Type: | feudal district duchy |
| Event Start: | Partition of the Duchy of Greater Poland |
| Year Start: | 1177 |
| Event End: | Unification of the Duchy of Greater Poland |
| Year End: | 1279 |
| P1: | Duchy of Greater Poland |
| S1: | Duchy of Greater Poland |
| Religion: | Roman Catholic |
| Flag Border: | no |
| Image Map Caption: | Political division of Greater Poland |
| Capital: | Poznań |
| Title Leader: | Duke |
| Leader1: | Odon of Poznań |
| Year Leader1: | 1177–1193 (first) |
| Leader2: | Przemysł II |
| Year Leader2: | 1273–1279 (last) |
The Duchy of Poznań (Polish: Księstwo poznańskie; Latin: Ducatus Posnaniensis) was a feudal district duchy in the Greater Poland, centered on the Poznań Land. Its capital was Poznań. The state was established in 1177, in the partition of the Duchy of Greater Poland, after the rebellion against Mieszko III. Duke Odon of the Piast dynasty become its first ruler.[1] It existed until 1279, when, it got united with duchies of Gniezno and Kalisz, under the rule of Przemysł II, forming the Duchy of Greater Poland.[2] It remained a fiefdom within the Duchy of Poland, until 1227, and after that, it become an independent state.[3]