Tehran Province (Persian: استان تهران) is one of the 31 provinces of Iran. Its capital is the city of Tehran, the national capital of Iran.

Tehran Province covers an area of 18,814 square kilometres (7,264 sq mi) and is located to the north of the Central Plateau of Iran. It was made a part of the First Region with its secretariat located in Tehran, upon the division of the provinces into 5 regions, solely for coordination and development purposes on June 22, 2014.

Tehran Province is situated in north-central Iran, lying on the southern slopes of the Alborz Mountains. The province’s location within the Alborz range gives it a diverse topography, with high mountains in the north and gradually descending plains toward the south. This geographical setting creates a varied climate, from cool alpine conditions to semi-arid lowlands.

The province of Tehran has over 12 million inhabitants and is Iran's most densely populated region. Approximately 86.5 percent reside in urban areas and 13.5 percent in rural areas of the province.

Tehran province has several archeological sites indicating settlements dating back several thousand years. Until 300 years ago, Rey was the most prominent of the cities of the province. However, the city of Tehran rose to become the largest city and capital of Iran by 1796, and since then has been the political, cultural, economic, and commercial nucleus of Iran.

Tehran has over 1,500 historical sites of cultural significance registered with the Cultural Heritage Organization of Iran. The oldest of these in Tehran Province is the remains of two sites in Firuzkuh County that date back to the fourth millennium BCE.

After the 2006 census, Karaj, Nazarabad, and Savojbolagh Counties were separated from the province in the establishment of Alborz province.

The majority of people living in Tehran province are ethnically Persian, and Tehran is the largest Persian-speaking city in the world.