Tenaga Nasional Berhad engages in the generation, transmission, distribution, and sale of electricity in Malaysia and internationally.

The company operates and maintains thermal generation facilities and hydroelectric power generating schemes, as well as supports independent power producers; and manages and operates the National Grid that is connected to Thailand's transmission system, as well as Singapore's transmission system at Senoko.

It also supplies fuel and coal for power generation; generates, distributes, supplies, deals in, and sells various energy sources, as well as provides related technical services; develops district cooling systems; operates and maintains co-generation works; manufactures, sells, and repairs distribution, power, and earthing transformers; and develops, owns, and manages dry bulk terminals.

In addition, the company provides turnkey contracting of transmission substations; repair and maintenance services to heavy industries and other related services; operation and maintenance services on telecommunication equipment and data centres; higher education, and telecommunication and IT infrastructure solution and services; research and development services in the areas of engineering, information technology, business, accountancy, and liberal studies; and training courses.

Further, it offers insurance and reinsurance products, parking facilities for motor vehicles, technical and laboratory, and consultancy and other services; manufactures and distributes power and general cables, and aluminum rods; operates an integrated district cooling systems for air conditioning systems of office buildings; assembles, manufactures, tests, reconditions, and distributes high and medium voltage switchgears, and control gears for transmission and distribution of electric power; and operates wind assets.

It primarily serves commercial, industrial, and residential customers.

The company was founded in 1949 and is headquartered in Kuala Lumpur, Malaysia.