Tremezzo is a comune (or municipality) of some 1,300 people in the Province of Como, in the Italian region Lombardy.

Tremezzo, which has an area of 8.4 square kilometres (3.2 sq mi), also borders the territory of the following communes: Lenno (south and west of Mezzegra), Menaggio (north of Griante), Grandola ed Uniti (inland from Menaggio) and, on the facing shore of the lake, Bellagio and Lezzeno.

As well as the capoluogo of Tremezzo, the area of the commune includes the frazione Rogaro, birthplace of the architect Pietro Lingeri.

Members of the family include 19th century German Romanticist novelist Clemens Brentano and his sister Bettina von Arnim.

The comune of Tremezzo was united with Mezzegra, Ossuccio, and Lenno to form a single municipality named Tremezzina following the election of the Major on 25 May 2014.