Tiarno di Sotto was a comune (municipality) in the Trentino in the Italian region Trentino-Alto Adige/Südtirol.

On January 1, 2010 it merged (with Pieve di Ledro, Bezzecca, Concei, Molina di Ledro and Tiarno di Sopra) in the new municipality of Ledro.

[1] It is located about 40 km southwest of Trento.