Jay Overmeer (born December 1, 1996) is a Dutch kickboxer, currently competing in the welterweight division of Glory. As of December 2022, he is ranked as the tenth best welterweight kickboxer in the world by Beyond Kickboxing and Combat Press.

Overmeer faced the future Glory middleweight champion Donovan Wisse at World Fighting League 5 : Champions vs. Champions on April 23, 2017. He lost the fight by unanimous decision.

Overmeer took part in the 2017 World Fighting League welterweight tournament, which was held on October 29, 2017. He captured the tournament title with unanimous decision victories over Abdelmouniem Mouyah in the semifinal and Darryl Sichtman in the final.

Overmeer participated in the 2019 King of Kings welterweight tournament. He was eliminated in the semifinals of the one-day tournament, as he lost to Ekrem Doruk by a narrow split decision, after an extra fourth round was contested. Overmeer faced the eventual tournament winner Chico Kwasi two years later, at a May 21, 2021, WFL event. He won the fight by unanimous decision, after knocking Kwasi down with a head kick.

Overmeerfaced Haris Biber at the August 21, 2021, World Fighting League event. He won the fight by a third-round technical knockout, as the in-ring official waved the fight off, judging Biber to have sustained too much damage. It was later revealed by Biber that he had suffered a broken nose and jaw.

Overmeer was booked to face the two-weight Enfusion champion Endy Semeleer for the inaugural Enfusion World Welterweight (-77kg) Championship at Enfusion #104 on November 12, 2021. He lost the fight by unanimous decision.

Overmeer made his Glory debut against Jos van Belzen at Glory 80 on March 19, 2022. He won the fight by technical knockout, after thrice knocking van Belzen down in the second round.

Overmeer faced Rodrigo Mineiro in his next Glory appearance, at Glory Rivals 1 on June 11, 2022. He won the fight by a first-round knockout, stopping Mineiro with a well-placed knee strike.