TOT Public Company Limited (Thai: 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. Since 2021, TOT PCL become National Telecom Public Company Limited after merger with CAT Telecom.