The International Olympic Committee selected the host city in the first round of voting in Durban, South Africa on Wednesday.
IOC President Jacques Rogge announced the election was over after just one round of the secret ballot among 95 members. He opened a sealed envelope and read the words: "The International Olympic Committee has the honor of announcing that the 23rd Olympic Winter Games in 2018 are awarded to the city of Pyeongchang."
Pyeongchang was considered an early favorite since it was barely defeated for the 2010 and 2014 games by Vancouver and Sochi. The two other cities that vied for the honor were Munich, Germany and Annecy, France.
Needing 48 votes for victory, Pyeongchang received 63 of the 95 votes cast. Munich received 25 and Annecy seven.
Pyeongchang, whose slogan is "New Horizons," campaigned on the theme that it will spread the Olympics to a lucrative new market in Asia and become a hub for winter sports in the region. It will be the first city in Asia outside Japan to host the Winter Games.
It was the first time an Olympic bid race with more than two finalists was decided in the first round since 1995, when Salt Lake City defeated three others to win the 2002 Winter Games.
The Korean victory followed the IOC's trend in recent votes, having taken the Winter Games to Russia (Sochi) for the first time in 2014 and giving South America its first Olympics with the 2016 Summer Games in Rio de Janeiro.
The Associated Press contributed to this story