Leutnant Johannes Klein (died 1926) was a German World War I flying ace credited with 16 confirmed and two unconfirmed aerial victories.
He became a fighter pilot in February 1917, and received his initial assignment to either Royal Prussian Jasta 27 or Royal Prussian Jasta 29. He switched to Royal Prussian Jasta 18 in August 1917, and scored his first victories there, downing a Spad on 16 August and a Sopwith Camel on 5 September. Klein then transferred to Royal Prussian Jasta 15, and scored the remainder of his wins between 30 March and 25 September 1918.
He was awarded the Royal House Order of Hohenzollern on 19 September 1918.