The Arab Socialist Union of Libya (Arabic: الاتحاد الاشتراكي العربي الليبي, Al-Ittiḥād Al-Ištirākī Al-ʿArabī Al-Liby) was a political party in Libya.
Many aspects of Muammar Gaddafi's Libyan socialist revolution were based on that of Gamal Abdel Nasser. Like Nasser, Gaddafi seized power with a Free Officers Movement, which, in 1971, became the Arab Socialist Union of Libya. Like its Egyptian counterpart, the Libyan ASU was the sole legal party, and was designed as a vehicle for integrated national expression rather than as a political party.
Bashir Hawady was the general secretary of the party. In May 1972 the Libyan ASU and the Egyptian ASU agreed to merge their two parties into a single body.