Lješanska nahija (Serbian Cyrillic: Љешанска нахија) is a historical region in eastern Montenegro. It was a nahija (sub-district) of the Ottoman Empire. In the administration of the Principality of Montenegro, the nahija was part of Old Montenegro, alongside Katun, Rijeka and Crmnica. The Gradac Monastery is located within the region.
Lješanska nahija included the area to the Riječka nahija, and was the most impoverished and smallest part of the Principality of Montenegro, consisting of several brotherhoods, which due to some differences among them (especially religious) could not in its entirety establish itself as other tribes.
The region was bordered by Lješkopolje, an Ottoman frontier which was not part of Montenegro prior to the Congress of Berlin (1878).
The toponym is derived from the Serbian (Slavic) masculine given name . The name (Lješanska nahija) is first mentioned in 1692. The three tribes of the nahija were Draževina, Gradac and Buronje. Traditionally, Vojvodas (The Dukes) of the tribe came from the House of Uskoković.