Gaius Julius Quadratus Bassus (70–117), was an office holder under the Roman Empire and a Romanized Galatian who served as suffect consul in May-August 105.
Quadratus Bassus was born in Pergamon, the son of Gaius Julius Bassus, who was Proconsul of Bithynia in 100/101. He served as a Legate at Judaea from 102/103 to 104/105. After his term as suffect consul Quadratus Bassus served as the governor of Cappadocia and Galatia (114/115), and later Syria (114/115). He was serving as Legatus Augusti pro praetore (governor) in the province of Dacia when he died in the Dacian revolt of 117.