The 2020–21 Turkish Airlines EuroLeague was the 21st season of the modern era of the EuroLeague and the 11th under the title sponsorship of Turkish Airlines. Including the competition's previous incarnation as the FIBA Europe Champions Cup, this was the 64th season of the premier basketball competition for European men's clubs. The season started 1 October 2020.

The EuroLeague, known as the Turkish Airlines EuroLeague for sponsorship reasons, is a European men's professional basketball club competition. The league is widely recognised as the top-tier men's league in Europe. The league consists of 18 teams, of which 16 are given long-term licences and wild cards, making the league a semi-closed league. The league was first organized by FIBA in 1958, subsequently by ULEB in 2000 and then solely the Euroleague Basketball.