The telecommunication sector is made up of companies that make communication possible on a global scale, whether it is through the phone or the Internet, through airwaves or cables, through wires or wirelessly. These companies created the infrastructure that allows data in words, voice, audio, or video to be sent anywhere in the world. The largest companies in the sector are telephone (both wired and wireless) operators, satellite companies, cable companies, and Internet service providers.

Not long ago, the telecommunications sector consisted of a club of big national and regional operators. Since the early 2000s, the industry has been swept up in rapid deregulation and innovation. In many countries around the world, government monopolies are now privatized and they face a plethora of new competitors. Traditional markets have been turned upside down, as the growth in mobile services outpaces the fixed-line and the Internet starts to replace voice as the staple business.