Giulio Lasso (died 1617) was an Italian architect, best known for his work in Palermo, Sicily. He was born in Florence.
His younger step-brother Orazio Borgianni (born c.1578), a sculptor, was trained by Lasso and probably travelled to Sicily with him.
Lasso's most famous work is the Quattro Canti, an eight sided piazza in the centre of Palermo. The result of a road straightening and widening scheme, the Quattri Canti is one of Sicily's first examples of the Baroque style of architecture, and is also an early example of architectural town planning.
Lasso did not live to see its completion and the project was eventually finished under the supervision of Mariano Smiriglio, who was the architect of the Palermo Senate.