The National Power Corporation (Filipino: Pambansang Korporasyon sa Elektrisidad, also known as NAPOCOR, NPC or National Power) is a Philippine government-owned and controlled corporation that is mandated to provide electricity to all rural areas of the Philippines by 2025 (known as "missionary electrification"), to manage water resources for power generation, and to optimize the use of other power generating assets.

Prior to the effectivity of the Electric Power Industry Reform Act (EPIRA) law or Republic Act No. 9136 on March 1, 2003 two years after its June 8, 2001 approval by President Gloria Macapagal Arroyo that deregulated the power industry by turning over NAPOCOR's operations, maintenance, and ownership of the Philippine power grid to another government-owned corporation National Transmission Corporation (TransCo) on March 1, 2003 as mandated on the said law that organized the industry into four sectors: generation, transmission, distribution, and supply, NAPOCOR was a vertically integrated power utility engaged in the production, transmission and distribution of electric power, used to be the largest provider and generator of electricity in the Philippines, and served as the operator and owner of the country's power grid and its related assets and facilities from its creation on November 3, 1936 to March 1, 2003, with TransCo as its then child agency from June 26, 2001 to March 2003. It was also the principal power provider for Manila Electric Company (Meralco), the only power distributor in the Metro Manila area and its nearby provinces (including all towns or cities such as Santo Tomas, Batangas on some of their respective provinces that cover the Meralco franchise).

NAPOCOR used to be the country's largest corporation in terms of revenue. Profitability however is a main concern now because it is in the business of missionary electrification that provides electricity to far-flung, off-grid remote areas and islands at subsidized rates. As a government owned and controlled corporation, NAPOCOR is subject to the scrutiny of the Commission on Audit (COA) and the Governance Commission for Government Owned and Controlled Corporations (GCG). It also manages 17 large dams and 11 watersheds in the country and continues to oversee the privatization of the government's remaining undisposed power assets. As of December 2015, NAPOCOR has a total of 1,735 megawatts (MW) of generating capacity, which includes 345 MW of small generators in small islands and off-grid locations and 1,390 MW in hydroelectric power plants and independent power producing plants in the main grids.

The National Power Corporation was originally organized as a non-stock, public corporation under Commonwealth Act No. 120 approved by President Manuel L. Quezon on November 3, 1936. The law nationalized the hydroelectric industry and reserved for the use of NPC, all streams, lakes and springs in the Philippines where power may be developed, subject to existing rights. In 1960, under Republic Act No. 2641, it was converted into a wholly government-owned stock corporation with a capitalization of ₱100 million.

The authorized capital stock was increased to ₱250 million under Republic Act No. 3043 passed on June 17, 1961, and was further increased to ₱300 million under Republic Act No. 4897 approved on June 17, 1967. A major event in the corporate existence of the NPC was the passage on September 9, 1971, of Republic Act. No. 6395 which gave birth to a revised charter for NPC. Under the revised charter, the activities and functions of the corporation were decentralized and carried out by three regional offices to be established in Luzon, Visayas and Mindanao. The charter, likewise, extended the corporate life of NPC up to the year 2036.

With the government's aim of promoting the economic welfare of the country through the attainment of total electrification, especially in rural areas, Presidential Decree No. 40 was issued on November 7, 1972, for the setting up of island grids with central/linked-up generating facilities and cooperatives for the distribution of power. The NPC, as the authorized implementing agency of the state, was entrusted with the responsibility of setting up transmission line grids and the construction of associated generating facilities in Luzon, Mindanao, and major islands of the country, including the Visayas.

In January 1974, President Ferdinand Marcos issued Presidential Decree No. 380 placing the NPC directly under the Office of the President. The move was intended to make the NPC a more efficient implementing arm of the government in the conservation and utilization of water resources and in the total electrification of the country. The Decree further boosted NPC's capitalization to ₱2 billion and its principal indebtedness, exclusive of interest, to ₱3 billion.

In December 1975, pursuant to the continuing effort of the President to make the government machinery more attuned and responsive to the needs of the service and of the people, the President decided to attach the NPC to the Department of Public Works, Transportation and Communication (now Department of Public Works and Highways). The transfer was effected by Letter of Implementation No.31 dated December 11, 1975, pursuant to Presidential Decree No.830 dated November 27, 1975, which extends ‘flexible and continuing authority to the President to restructure the Office of the President.”