TOT Public Company Limited (ทีโอที) is a Thai state-owned telecommunications company. Originally established in 1954 and corporatized in 2002, TOT used to be known as the Telephone Organization of Thailand and TOT Corporation Public Company Limited. TOT's main line of business is fixed line telephony, although it has several other businesses, including mobile telephony. Its current Chairman of the Board of Directors is Panthep Jamradroamrun.
First use of the telephone in Thailand began during the reign of King Rama V in 1881 with a telephone line constructed between the Bangkok, and Paknam, in Samut Prakarn, located a short distance south of Bangkok along the Chao Phraya river for the purpose of informing Bangkok of the news concerning the arrival and departure of ships at Paknam. 
The Telephone Organization of Thailand was founded by the Thai government in 24 February 1954. A state enterprise under the Ministry of Transport and Communications, it incorporated the Telephone Technician Unit under The Post and Telegraph Department. It originally had 732 staff members and a budget of 50 million Baht. The TOT provided telephone services in Bangkok Metropolis, which included Wat Lieb, Bangrak, Ploenchit and Samsaen Exchanges.
TOT was transformed from a state-own enterprise under the control of the Transport and Communication Ministry to a public company named TOT Corporation Public on July 31, 2002.
Corporate status change and the aftermath of the 2006 coup
Under the deposed government of Thaksin Shinawatra (2001–2006), the TOT was made into a corporation and plans were under way to privatise a portion of the state enterprise through an IPO in the Stock Exchange of Thailand. These plans were cancelled after the Thaksin-government was overthrown by a coup in 19 September 2006. Soon after the coup, the junta of General Surayud Chulanont announced plans to merge TOT with rival state telecom enterprise CAT Telecom (formerly the Communications Authority of Thailand).
The junta also appointed junta Assistant Secretary-General General Saprang Kalayanamitr to become the new Chairman of the Board of Directors of TOT. General Saprang's first move as TOT Chairman was to hand-pick three Army colonels and controversial Thaksin-critic Vuthiphong Priebjrivat to sit on the state enterprise's Board of Directors.
The junta also cancelled the Thaksin government's telecom excise tax policy. The Thaksin government imposed an excise tax on privately offered fixed and cellular services, and then allowed telecom companies to deduct the amount they paid in excise tax from concession fees they had to pay to state concession owners TOT and CAT Telecom. The total amount paid by the private telecom firms did not change. The Surayud government's excise tax cancellation meant that TOT and CAT Telecom would receive their full concession payments. However, TOT and CAT were then forced to increase their dividends to the Ministry of Finance to account for their increased income.
In December 2009, TOT became Thailand’s first 3G mobile phone service provider launching 3G mobile phone service (Phase 1) via the brand TOT3G, by enhancing 584 base stations in Bangkok and its vicinity to accommodate 500,000 numbers for the service and with a goal of nationwide coverage within the end of 2011.
TOT3G is also a host network operator who hosts Mobile Virtual Network Operators (MVNO).
Currently, TOT3G has five MVNOs on its network:
- i-mobile 3GX
- 365 3G All service migrated to TOT3G As of 10 October 2013[update]
- i-kool Real 3G
- Thai National Archives
- TOT, About TOT
- The Nation, Call for end to policy corruption, 16 October 2006
- Bangkok Post, THAILAND: New TOT board may order cleanup 31 January 2007
- The Nation, Telecom excise tax revoked, 24 January 2007
- "Thailand's MVNO market" Yozzo.com
- "TOT takes over the remaining customers from the MVNO 365-3G". Yozzo.com. Retrieved 2013-09-27