NATO-4 is a communications satellite system serving the North Atlantic Treaty Organization (NATO) and the British Ministry of Defense. NATO 4A was the first of two new-generation comsats offering secure military and diplomatic voice and data communications to NATO member nations and troops in the field.

The satellites offered spot beam and global coverage to reach a wide range of ground stations and ships at sea. The communications package housed four SHF and two UHF channels. The payload was provided by Marconi Space Systems; the satellites were built by British Aerospace. Based on the Skynet 4 design, it was box-shaped, measuring 2.1 m high by 1.9 m long by 1.4 m wide. Solar arrays spanned 16 m and provided 1,200 W at end of life. The satellite had a 7-year design life.

NATO 4B was retired in 2016 and was moved into a graveyard orbit above the geostationary belt.