Martha Maria Norelius (January 22, 1909 – September 25, 1955) was a Swedish-born American competition swimmer, Olympic gold medalist and former multiple world record-holder.
Norelius won three gold medals at the 1924 and 1928 Olympics, in the 400-meter freestyle in 1924, and the 400-meter freestyle and 4×100-meter freestyle relay events in 1928. Between 1925 and 1929, she won 11 individual Amateur Athletic Union (AAU) titles and set at least 19 world and 30 American records.
Norelius was the daughter of Swedish Olympic swimmer Charles Norelius who was also her swimming coach. In 1929 she turned professional and won the ten-mile Wrigley Marathon in Toronto. There she met Canadian Olympic rower Joseph Wright, Jr., and later married him on March 15, 1930.