Palazzo dei Trecento (also called Palazzo della Ragione) is a building in Treviso, Veneto, northern Italy, located in the Piazza dei Signori. It is home to Treviso municipal council.
The palace was erected in the 13th and 14th centuries, as the seat of the Maggior Consiglio ("Highest Council"), the main administrative council in the city. Built in brickworks, it has two floors, the lower one entered through a loggia. The upper floor has three triple mullioned windows.
Internally, there are remains of frescoes painted from the 14th to the 16th centuries by Venetian artists, depicting coat of arms and themes of civil power and justice. On the southern walls are a Madonna with Child and "St. Liberalis with Peter and the Cardinal Virtues.
In 1944 the palace was bombed by Allied planes and nearly destroyed.