The United Nations Information Organisation (UNIO) was the first international agency of the Allied powers participating in World War II and was also the first organisation to incorporate in its title the "United Nations" name. Its history began with the establishment of the Inter-Allied Information Committee and Center in New York in September 1940, as a clearing house for the information services of the nations at war with the Axis powers.

A year later a similar committee by the British Ministry of Information (MOI) was established in London. Following organisational changes in November 1942 the New York Information Center adopted the name United Nations Information Office while its controlling organ had become the United Nations Information Board. In London, this change was paralleled by the dissolution of the Inter-Allied Section of MOI and a new, truly international information office was opened in November 1943. After further organisational and functional developments a United Nations Information organisation was officially constituted in the United Kingdom in May 1944. Later, in January 1945, the New York based office also changed its name to United Nations Information Organization.