Kamianets-Podilskyi Castle (Ukrainian: Кам'янець-Подільська фортеця; Polish: twierdza w Kamiencu Podolskim;) is a former Ruthenian-Lithuanian castle and a later three-part Polish fortress located in the historic city of Kamianets-Podilskyi, Ukraine, in the historic region of Podolia in the western part of the country. Its name is attributed to the root word kamin', from the Slavic word for stone.
Historical accounts date the Kamianets-Podilskyi Castle to the early 14th century, although recent archaeological evidence has proved human existence in the area back to the 12th or 13th century. Initially built to protect the bridge connecting the city with the mainland, the castle sits on top of a peninsula carved out by the winding Smotrych River, forming a natural defense system for Kamianets-Podilskyi's historic Old Town neighborhood.
Its location on a strategic transport crossroad in Podolia and made the castle a prime target for foreign invaders, who rebuilt the castle to suit their own needs, adding to its multicultural architectural diversity. Specifically, the complex consists of the Old Town fortified by King Casimir IV, the Old Castle rebuilt by Kings Sigismund I and Stephen Bathory, and the New Castle founded by Kings Sigismund III and Wladyslaw IV. However, in spite of the many architectural and engineering changes to the original structure, the castle still forms a coherent architectural design, being one of the few medieval constructions in Ukraine that is relatively well preserved.
Along with the Old Town neighborhood, the castle is listed as part of the National Historical-Architectural Sanctuary "Kam'ianets" and the National Environmental Park "Podilski Tovtry". The complex is a candidate UNESCO World Heritage Site, nominated in 1989 by the Ukrainian representatives, and also one of the Seven Wonders of Ukraine. Today, the Kamianets-Podilskyi Castle is the most recognized landmark of the city, serving as an important regional and national tourist attraction.