Giulio Quaglio(1610-1658 or after) was an Italian painter of frescoes.
He was a follower of Tintoretto. He is known to have worked in Vienna, Salzburg, and Ljubljana. His son, Giulio the younger, was born in Como and established himself in the Friuli about the end of the 17th century. He is best known for frescoes at the chapel of the Monte di Piete, at Udine. He died in 1720. They are both part of a large family of artists and architects from the town of Laino, between Lake Garda and Lake Como, and which included Giuseppe Quaglio and his sons Lorenzo the younger, Simon, and Domenico; Lorenzo Quaglio the elder; and Giovanni Maria Quaglio and his son.