Grega Žemlja (born 29 September 1986) is a retired Slovenian tennis player. He has won five singles titles and one doubles title on the ATP Challenger Tour. In 2012, he reached the third round of the US Open, the first Slovenian male player ever to reach that stage in a Grand Slam tournament. He is also the first Slovenian ATP player who in 2013 reached third round at Wimbledon. He reached his highest ATP ranking of World No. 43 in singles in May 2013, becoming the first Slovene ATP player to reach the top 50. Žemlja also became the first Slovene player earning over 1 million US dollars in prize money, and he was the highest-paid Slovene player in history until he was passed by Blaz Kavcic. He represented his country as a member of Slovenia Davis Cup team.