Established in May 1948 to assist the United Nations Mediator and the Truce Commission in supervising the observance of the truce in Palestine.

Since then, UNTSO has performed various tasks entrusted to it by the Security Council, including the supervision of the General Armistice Agreements of 1949 and the observation of the ceasefire in the Suez Canal area and the Golan Heights following the Arab-Israeli war of June 1967.

At present, UNTSO assists and cooperates with the United Nations Disengagement Observer Force (UNDOF) on the Golan Heights in the Israel-Syria sector, and the United Nations Interim Force in Lebanon (UNIFIL) in the Israel-Lebanon sector. UNTSO is also present in the Egypt-Israel sector in the Sinai. UNTSO maintains offices in Beirut and Damascus.