Conservative Party leader Erna Solberg, nicknamed "Iron Erna", will become Norway's new prime minister, leading a centre-right coalition government which will probably include an anti-immigration party.
Preliminary results from the oil-rich country's parliamentary elections shows the Conservative Party with 26.8% of votes, the best result for the party in 28 years.
Ms Solberg, who will be Norway's second female prime minister after Gro Harlem Brundtland, thanked the voters for a historic victory. "The voters had the choice between 12 years of red-green government or a new government with new ideas and new solutions," she said.
Current prime minister Jens Stoltenberg, who has led Norway for eight years, conceded defeat, saying his Labour Party tried "to do what almost no one has done, to win three elections in a row, but it turned out to be tough".
The discovery of oil and gas in Norway's waters in the 1960s turned the Scandinavian nation into one of the richest in the world, with a strong welfare system and a high living standard.
The oil wealth helped it withstand Europe's financial crisis and retain low unemployment throughout Mr Stoltenberg's years in power. Still, the Conservative Party has managed to attract votes amid pledges to increase the availability of private health care and cut taxes on assets over £90,000.
Frank Aarebrot, professor of comparative politics at the University of Bergen, said the election campaign was dominated by classical welfare issues such as better care for the elderly, improved hospitals and better schools. Yet none of the parties suggested that Norwegians should have to pay for things such as hospital visits, college education or elderly care. "Everybody agrees that should be for free," he said.
The Conservative Party has said for the first time that it is prepared to form a coalition government with the anti-immigration Progress Party, which was the third biggest party in the election. Ms Solberg will now probably begin negotiations with it, as well as with the Liberal Party and the Christian Democrats.
According to preliminary results, she needs the support of all three parties for a majority government, but could end up running a minority government with the Progress Party with support from the two others, if they refuse to share power with the Progress Party.
This was the first parliamentary election since Anders Breivik - who was a member of the Progress Party before he lost faith in democracy - killed 77 people in 2011 and 33 survivors of the massacre were seeking national office in the election.