Mary Louise Stepan (born February 2, 1935) is an American former competition swimmer and Olympic medalist.
As a 17-year-old, Stepan represented the United States at the 1952 Summer Olympics in Helsinki.
She received a bronze medal as a member of the third-place U.S.
team in the 4×100-meter freestyle relay, together with teammates Jackie LaVine, Jody Alderson and Evelyn Kawamoto.
Individually, Stepan also competed in the women's 100-meter freestyle, advanced to the event final, and finished seventh overall with a time of 1:08.0.Stepan later married Richard Wehman and had four children.
She was formerly a member of the United States Olympic Committee.