Hyacinthe Eléonore Klosé (11 October 1808 – 29 August 1880) was a French clarinet player, professor at the Conservatoire de Paris, and composer.
Klosé was born in Corfu (Greece). He was second clarinet at the Théâtre Italien to Frédéric Berr beginning in 1836, then to Iwan Müller following Berr's death in 1838, finally becoming solo clarinettist when Müller left in 1841.
Klosé was also noted for his design improvements to the clarinet using the principles laid down by
Theobald Boehm in his innovative work on the flute keywork. From 1839 to 1843, he enlisted the help of Louis-August Buffet of Buffet-Crampon fame, an instrument-making technician, to construct what is known today as the Boehm system clarinet.
He died in Paris.