Heinrich Ernst Otto (Henner) Henkel (born on October 9, 1915, Poznań, German Empire - died January 13, 1943 at Voronezh) was a German tennis player.
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.
In March 1937 he became the singles champion at the Cairo International Championships defeating Giorgio de Stefani in the final in straight sets and also won the doubles title partnering Von Cramm.
Between 1934 and 1939 Henkel played 66 matches for the German Davis Cup team in 27 ties. He won 49 matches, lost 17 and was particularly successful in doubles, winning 16 of 20 matches partnering Gottfried von Cramm, Georg von Metaxa and Roderich Menzel.
Henner Henkel was killed in action during World War II on the Eastern Front at Voronezh during the Battle of Stalingrad while serving in the Wehrmacht (German Army).
Since 1950 the German junior team championship has been called the "Große Henner Henkel-Spiele" and since 1963 a commemorative tournament, "Henner-Henkel-Gedächtnisturnier", has been held in Erfurt.