The province of Rieti is a province in the Lazio region of Italy. Its capital is the city of Rieti. Established in 1927, it has an area of 2,750.52 square kilometres (1,061.98 sq mi) with a total population of 157,887 people as of 2017. There are 73 comuni in the province.

Lazio or Latium is one of the 20 administrative regions of Italy. Situated in the central peninsular section of the country, it has 5,714,882 inhabitants and a GDP of more than €197 billion per year, making it the country's second most populated region and second largest regional economy after Lombardy. The capital of Lazio is Rome, which is also the capital and largest city of Italy, and completely encircles a foreign nation.