A telephone company^{[lower-alpha 1]} is a kind of electronic communications service provider, more precisely a telecommunications service provider (TSP), that provides telecommunications services such as telephony and data communications access. Many traditional solely telephone companies now function as internet service providers (ISPs), and the distinction between a telephone company and ISP has tended to disappear completely over time, as the current trend for supplier convergence in the industry developes.^[2] Additionally, with advances in technology development, other traditional separate industries such as cable television, Voice-over IP (VoIP), and satellite providers offer similar competing features as the telephone companies to both residential and businesses leading to further evolution of corporate identity have taken shape.

Due to the nature of capital expenditure involved in the past, most telecoms were government owned agencies or privately-owned monopolies operated in most countries under close state-regulations. But today there are many private players in most regions of the world, and even most of the government owned companies have been opened up to competition in-line with World Trade Organization (WTO) policy agenda. Historically these government agencies were often referred to, primarily in Europe, as PTTs (postal, telegraph and telephone services).^[3] Telephone companies are common carriers, and in the United States are also known as local exchange carriers. With the advent of mobile telephony, telephone companies now include wireless carriers, or mobile network operators and even satellite providers (Iridium).

Over time software companies have also evolved to perform telephone services such as: Net2Phone, WhatsApp, and others.

In 1913, the Kingsbury Commitment allowed more than 20,000 independent telephone companies in the United States to use the long distance trunks of Bell Telephone Company.^[4][5]

• Comedian Lily Tomlin frequently satirized the telephone industry (and the country's then-dominant Bell System in particular) with a skit playing the telephone operator Ernestine. Ernestine, who became one of Tomlin's trademark characters, was perhaps most famous for the following line: "We don't care; we don't have to. We're the phone company."
• In the satirical 1967 film The President's Analyst, The Phone Company (TPC) is depicted as plotting to enslave humanity by replacing landlines with brain-implanted mobile phones.
• In the 1988 video game Zak McKracken and the Alien Mindbenders, The Phone Company (TPC) was used by the Caponian aliens to secretly reduce the intelligence of humans.