Louis Straight Clark (February 10, 1925 – February 10, 1995) was an American tennis player in the mid-20th century. He was born in Des Moines, Iowa. He played college tennis at the University of Southern California. A member of the US Davis Cup team, he was 5–0 in matches in 1953 and 1954 (and the latter year, a member of the winning team). In 1954, he won the singles title at the tournament in Cincinnati, defeating Sammy Giammalva, Sr., in the final in three straight sets.