The ITU saw its inception in 1865 when 20 countries jointly signed the framework agreement at the International Telegraph Convention to adopt common rules and standard equipment for transmitting telegraph messages across international lines. The International Telegraph Union was launched to provide a forum to turn this agreement into a living framework through the evolution of international communications technologies, facilitating dialogue and enabling amendments to the initial agreement. Within a matter of years, the International Telegraph Union was busily devising legislation aimed at developing international standards for telephony and radio communications, further solidifying its role as the primary body governing and promoting international communications. In 1932, the Telegraph Union merged with the International Telegraph Convention of 1865 and the 1906 International Radiotelegraph Convention into one agreement called the International Telecommunications Convention, and in 1934 changed its name to the International Telecommunications Union (ITU), assuming responsibility for promoting and standardizing all international communications.

The ITU became a special agency of the United Nations in 1947 under an agreement aimed at modernizing the union. In 1989, at a Plenipotentiary Conference held in Nice, France, the ITU took responsibility for spear-heading technical telecommunications assistance to developing countries, placing such activities on a par with their traditional standardization and coordination activities. Through the Telecommunications Development Bureau, established in 1990, technological developments in telecommunications are met with new initiatives from the ITU aimed at integrating these innovations into the infrastructures of developing countries, thereby connecting them to a broader world network.

In early 2000s, the ITU took on the leadership role in the development of a Global Information Infrastructure (GII), an international network aimed at providing universal access to modern telecommunications and information technologies so as to level the playing field between nations and help integrate and further the global economy. In this way, the ITU worked diligently to bridge the digital divide, a contemporary situation within what the ITU refers to as the "telecommunications gap." The ITU saw telecommunications infrastructure as the principal problem underlying the digital divide, and promoted itself not so much as a regulator but as a facilitator for different policymakers from across the world to hammer out compromises, insisting that its regulatory scope was limited to ensuring open access to telecommunications.