World Information Society Day was proclaimed to be on 17 May by a United Nations General Assembly resolution, following the 2005 World Summit on the Information Society in Tunis.

The day had previously been known as World Telecommunication Day to commemorate the founding of the International Telecommunication Union on 17 May 1865. It was instituted by the Plenipotentiary Conference in Malaga-Torremolinos in 1973.