Gustav "Justav" Jaenecke (22 May 1908 – 30 May 1985) was a German ice hockey player who competed in the 1928 Winter Olympics, in the 1932 Winter Olympics, and in the 1936 Winter Olympics, and tennis player who played in three International Lawn Tennis Challenge ties for Germany.
He was born in Berlin, German Empire and died in Bonn, West Germany.