Palacio Vasallo, Municipal council building in central Rosario, Argentina.

Palacio Vasallo is a palace in Rosario, Argentina, designed by engineer Alejo Infante and completed in 1911. Its pale grey stone facade has a rounded central bay topped by a ribbed dome and small spire, with two dark wooden doors with arched glass tops at street level. Inside, a wooden staircase with a reddish-brown carpet runner and brass rods leads up past dark wood paneling, a large cabinet holding a white bust, and a dark statue on a pedestal.

Bartolomé Vasallo, a surgeon born in Gualeguay in 1874 and settled in Rosario from 1898, had the house at Córdoba 501 built in 1911 by engineer Alejo Infante. He died in 1943 and left the residence to the municipality. The Deliberative Council moved there from the Palacio de los Leones, held its first session on 25 May 1952, and in December 1951 auctioned most of Vasallo's art collection for 332,000 pesos, part of which paid for fitting out the building.

The building bears the name of surgeon Bartolomé Vasallo, born in Gualeguay in 1874 to Genoese parents, who settled in Rosario in 1898 and worked as chief surgeon at the Hospital Rosario. He donated the house and his art collection intending to create a Vasallo Museum, but the Deliberative Council auctioned most of the works in December 1951; the rest stayed in the building or went to the Museo Histórico Provincial Dr. Julio Marc.

The building stands at the corner of Córdoba 501 and 1.º de Mayo, facing the National Flag Memorial. Its facades are clad in imitation Paris stone, though the base is hidden under layers of paint. The council chamber was modernised and the dome restored in works inaugurated in November 2017.

The legislative chamber features modern technology with displays showing voting results and attendance information as sessions happen. The seats are specially designed Pampa models that fold automatically, allowing the space to adapt during meetings.