Heinrich Ernst Otto (Henner) Henkel (born 9 October 1915, Posen, German Empire – died 13 January 1943 at Voronezh) was a German tennis player. Henkel learned to play tennis at the Rot-Weiss Tennis Club in Berlin and was the German junior champion in 1932 and 1933. Henkel was the second German, after Gottfried von Cramm, to win the singles title at the French Championships in 1937. The same year, he and Gottfried von Cramm won the Roland Garros doubles title. Later that year they also won the US Championships doubles title defeating Americans Don Budge and Gene Mako in three straight sets.