Qadisiyah (Arabic: القادسية‎) is one of the governorates of Iraq. The administrative center is the city of Ad-Diwaniya. Other large cities are Afaq, Al-Hamza, Ash-Shamia, Gammas, Ash-Shinafiya, Ed-Daggar.
It is located in the center of Iraq, mostly in the interfluve of the Tigris and Euphrates. The center of the governorate is the city of Ad-Diwaniya. Until 1976, Qadisiyah was part of the province of Al-Diwaniya.
The Governor is Salim Hussein Alwan. The previous governor, Khalil Jalil Ganza, was killed on 11 August 2007 in a bomb attack.

The name of the governorate comes from the name of the historical city of Qadisiya, which became the site of the Battle of Qadisiyah.
On June 6, 2017, the Council of Ministers of the Republic of Iraq approved the change of the province’s name from Qadisiyah to Diwaniyah.