1583 Antilochus /ænˈtɪləkəs/ is a large Jupiter trojan from the Greek camp, approximately 108 kilometers (67 miles) in diameter. It was discovered on 19 September 1950, by Belgian astronomer Sylvain Arend at Uccle Observatory in Belgium, and later named after the hero Antilochus from Greek mythology. The dark D-type asteroid belongs to the and has a rotation period of 15.9 hours. It forms an asteroid pair with 3801 Thrasymedes.