PLDT Inc., (PSE: TEL, NYSE: PHI), formerly known as the Philippine Long Distance Telephone Company (Filipino: Kompanya ng Teleponong Pangmalayuan ng Pilipinas), is the largest telecommunications and digital services company in the Philippines and the most known internet service provider. The latest consolidated service revenues reported for the first three quarters of 2016 is at ₱125.4 billion, and net income at ₱15.9 billion.

PLDT was established on November 28, 1928, by a Philippine Government act. Philippine legislature and approved by then Governor-General Henry L. Stimson by means of a merger of four telephone companies under operation of the American telephone company GTE. Known as Act 3436, the bill granted PLDT a 50-year charter and the right to establish a Philippine telephone network linking major points nationwide. However, PLDT had to meet a 40-day deadline to start implementing the network, which would be implemented over a period of one to four years.

By the 1930s, PLDT had an expansive fixed-line network and for the first time linked the Philippines to the outside world via radiotelephone services, connecting the Philippines to the United States and other parts of the world.

Telephone service in the Philippines was interrupted due to World War II. At the end of the war, the Philippines' communications infrastructure was in ruins. U.S. military authorities eventually handed over the remains of the communications infrastructure to PLDT in 1947, and with the help of massive U.S. aid to the Philippines during the 1940s and 1950s, PLDT recovered so quickly that its telephone subscribers outpaced that of pre-war levels by 1953.

On December 20, 1967, a group of Filipino entrepreneurs and businessmen led by Ramon Cojuangco took control of PLDT after buying its shares from the American telecommunications company GTE. The group took control of PLDT's management on January 1, 1968, with the election of Gregorio S. Licaros and Cojuangco as chairman and president of PLDT, respectively. A few months later, PLDT's main office in Makati (known today as the Ramon Cojuangco Building) was opened, and PLDT's expansion programs begin, hoping to bring reliable telephone services to the rural areas.

PLDT was permitted to operate during Martial Law. During the 1970s, PLDT was nationalized by the government of then-President Ferdinand Marcos and in 1981, in compliance of then existing policy of the Philippine government to integrate the Philippine telecommunications industry, purchased substantially all of the assets and liabilities of Republic Telephone Company, becoming the country's telephone monopoly. Under this monopoly, service expansion were severely curtailed or practically nonexistent. In the Martial Law years people would apply for phone service only to wait for years and years on end behind an impossibly long application backlog. It is not unheard of for people and small businesses back then to barter for a single telephone line in the black market for tens of thousands of pesos. The incumbent Singaporean Prime Minister Lee Kuan Yew referred to the situation when visiting the Philippines during the term of President Fidel V. Ramos. He said, albeit in jest, “In the Philippines 95% of the population has no telephone, while the remaining 5% are waiting for that dial tone.”

After President Marcos was overthrown in 1986, the company was re-privatized as Ramon's son, Antonio "Tonyboy" O. Cojuangco, Jr. became PLDT chief. By 1995, with the passage of the Telecommunications Act and the subsequent deregulation of the Philippine telecommunications industry, the company has been de-monopolized.

In 1998, Hong Kong-based First Pacific Company Ltd. acquired a 17.5% stake in PLDT making it the majority owner of the conglomerate. Following the acquisition by the First Pacific group, Manuel V. Pangilinan became the new president and CEO of PLDT, replacing Cojuangco, who assumed the post of Chairman until 2004.

On April 2016, the company, then known as the Philippine Long Distance Telephone Company, dropped the "long distance telephone" from its corporate name and has was renamed PLDT Inc. Its board of directors approved the new corporate name to reflect on the company's new range of services, mainly focusing on data services. On June 13, 2016, PLDT and its subsidiary Smart unveiled their new logos and identity as part of the company's continuing digital pivot.

PLDT acquired 51.55% of the shares of Digital Telecommunications Philippines from JG Summit Holdings in March 2011 with the cost of ₱69.2 Billion. Because of this, the shares of Digitel and JG Summit in the PSE surges while PLDT's shares remained unchanged. In the deal, JG Summit will have a 12% share in PLDT. It was finalized by the National Telecommunications Commission on October 26, 2011.

Twenty percent of MERALCO shall be sold to PLDT, according to the Lopez family who owns the Philippine's largest electric distributor on March 13, 2009. The deal is set to be done in the third quarter of 2009 with the cost of 20 billion pesos. The said action was done to prevent the hostile takeover of San Miguel Corporation, which already owns a large portion of MERALCO.

PLDT operates its wireless cellular services through its subsidiaries, namely Smart, TNT, and Sun Cellular.

In 1998, MediaQuest Holdings, Inc., a wholly owned subsidiary of the PLDT Beneficial Trust Fund, acquired Nation Broadcasting Corporation from the joint consortium of the Yabut family and real estate magnate Manny Villar. In 2007, MediaQuest bought the shares of GV Broadcasting Systems, a licensed direct-to-home (DTH) satellite television provider from Satventures Inc. of the Galang family. With this, GV changed its corporate name to MediaScape Inc.

On March 2, 2010, PLDT announced that its subsidiary, MediaQuest Holdings, Inc., has acquired 100 percent of TV5 Network (TV5) and Primedia Inc from Media Prima and former PLDT Chairman Antonio "Tonyboy" O. Cojuangco, Jr.

The Company's ownership is divided among the public (53.86%), Philippine Telephone Investments Corporation (12.05%), Metro Pacific Resources, Inc. (9.98%); non-Philippine subsidiaries of First Pacific Company Limited (25.6%), NTT DoCoMo, Inc. (14.5%), NTT Communications Corp. (5.85%) and Manuel V. Pangilinan (0.11%).

In October 2015, PLDT introduced so-called "volume boosters" (instead of 30% bandwidth throttling in 2014 and 256kbit/s bandwidth throttling in 2015) when exceeding monthly 30GB to 70GB bandwidth cap for TD-LTE connection plans (Ultera). "In case your usage exceeds your monthly volume allowance, you can still enjoy the internet by purchasing additional volume boosters. Otherwise, connectivity will be halted until your monthly volume is refreshed on your next billing cycle." Globe followed the suit with a similar "volume boost" arrangement.

In 2015, PLDT increased lock-in period for TD-LTE connection plans from 24 to 36 months (3 years) with the pre-termination fee equal to the full balance for the remaining period. After the lock-in period the contract is automatically renewed for another 36 months subject to the same terms and conditions. As of now the Globe lock-in period is still 2 years with no pre-termination fee outside of the lock-in period. The PLDT TD-LTE contract allows PLDT to change the terms and conditions at any time with the only way left for subscribers to opt out of the altered service through paying the full pre-termination fee: "8.3 Modification. SBI reserves the right at its discretion to modify, delete or add to any of the terms and conditions of this Agreement at any time without further notice. It is the Subscriber’s responsibility to regularly check any changes to these Terms and Conditions. The Subscriber’s continued use of the Service after any such changes constitutes acceptance of the new Terms and Conditions." Even as the Consumer Act of the Philippines states "Unfair or Unconscionable Sales Act or Practice ... the following circumstances shall be considered ... that the transaction that the seller or supplier induced the consumer to enter into was excessively one-sided in favor of the seller or supplier", the practice of inducing extremely long term contracts with the ultimate pre-termination penalty has not been legally challenged yet.