Norway is to buy 48 F-35 Joint Strike Fighters from Lockheed Martin, in a deal worth about $US2.54 billion to replace its F-16 warplanes in 2016-2020.
Norway says that it needs new-generation jets partly to monitor its northern seaboard, where Russia has boosted military activities in recent years.
The government says total costs over the lifetime of the aircraft are estimated at 145 billion Norwegian crowns ($US20.43 billion).
Saab Gripen of Sweden was also in contention for the contract which will be the biggest defence investment in Norway's history.
Prime Minister Jens Stoltenberg said on Thursday the US planes would cost 18 billion Norwegian crowns - 6 billion crowns cheaper than the Gripens.
Defence officials said that stealth technology was a feature that put the F-35 ahead of others.
Norway has participated in the development of the JSF with other NATO members. The Gripen was been the only other jet considered, after the Eurofighter dropped out of the competition.