Sven Charles Otto Wennergren (7 February 1889 – 3 January 1978) was a Swedish tennis player[1] who competed at the 1912 and 1924 Summer Olympics.

[4] He and Carl-Olof Nylén reached the quarter-finals in men's doubles, losing to Harry Kitson and Charles Winslow of South Africa, who went on to win the gold medal.

[2] In singles competition, he won his first three matches and lost in the fourth round to Count Ludwig von Salm-Hoogstraeten, who was representing Austria.

[1] He was a one-time Danish covered courts champion by winning the 1921 mixed doubles alongside home favorite Agnete Goldschmidt.

His partner in men's doubles was Henning Müller; the pair reached the quarter-finals, where they lost to the eventual winners of the bronze medal, Jean Borotra and René Lacoste of France.