Constant Lestienne (French pronunciation: ; born 23 May 1992) is a French professional tennis player. He competes mainly on the ITF Men's Circuit and ATP Challenger Tour. He has won two ATP Challenger Tour singles titles. In addition, he has won five singles titles and three doubles titles in the ITF Men's Circuit.
Lestienne reached his first career ATP Tour singles main draw (where he lost in the first round to Pablo Carreño Busta) at the 2015 Estoril Open after winning two singles qualifying matches.
In September 2016 Lestienne was suspended for seven months and fined $10,000 by the International Tennis Federation for betting on tennis matches. The Tennis Integrity Unit (TIU) in cooperation with French online gambling regulator ARJEL found that Lestienne had bet on 220 tennis matches between February 2012 and June 2015. None of these matches were his own. Half of the ban was suspended and his fine would be halved if he assisted the TIU.