Handel, who is reportedly the first Republican woman to be elected in the Congress from Georgia, won 52.7% of the votes, while Ossof won 47.3% of the votes.
According to CNN, Ossoff had called Handel to congratulate her for the victory.
Handel said, "He was more than gracious and he thanked me for a spirited campaign. And I wish him and his fiancee Alisha Kramer all the best in the new life that they are going to be starting."
Congratulations to Karen Handel on her big win in Georgia 6th. Fantastic job, we are all very proud of you!— Donald J. Trump (@realDonaldTrump) June 21, 2017
She went on to extend her thanks to the US President, who has supported her during the campaign.
More than 100 attendees at Hyatt Regency in Northern Atlanta, celebrated Handel's victory.
The election was to replace the Health and Human Services Secretary Tom Price in a seat Donald Trump carried by just a single point in 2016.