Quentin Halys (French pronunciation: ; born 26 October 1996) is a French professional tennis player. Halys has a career-high ATP singles ranking of world no. 102 attained on 5 February 2018.
Quentin Halys reached four Junior Grand Slam finals, three in doubles and one in singles. Of the four finals, Halys won the 2014 French Open partnering Benjamin Bonzi. He reached a career high combined (singles and doubles) of World No. 03 on March 31, 2014. He ended his junior career with a 98–44 record on singles and 83–35 on doubles.
Quentin played in his first ITF Junior Circuit tournament in 2010 at the G4 Tournoi International de Clermont-Ferrand, as a wildcard. He lost in the first round. He reached his first final later that year, at the G5 International Junior Saint-Cyprien, in doubles. In an all-French final, Halys and Armel Rancezot lost in the super tiebreak against Julien Delaplane and Alexandre Favrot. Starting 2011, Halys entered a 17–match win streak, winning consecutively the 1st and 2nd Qatar ITF Junior Open, breaking through the qualifiers of both tournaments to win his first two singles titles. He also finished runner-up in the 1st tournament doubles. He streak was sniped by Belgian Clement Geens, at AEGON Junior International Nottingham, a 2-week G4 tournament. Quentin would reach the final in both singles and doubles of the 2nd week, but he won the doubles only. He would win another doubles titles in July of that year, at the Leeuwenbergh ITF G4 Junior Championships. Halys finished 2011 by playing for France at the Junior Davis Cup, where his country finished 3rd that year.