Sylvia Eliina Ruuska (July 4, 1942 – February 7, 2019) was an American former competition swimmer, Olympic medalist and former world record-holder in two events.

[1] She captured a silver medal by swimming for the second-place U.S. team in the women's 4×100-meter freestyle relay.

[1] On June 27, 1958, she became the first woman to set an official world record in the 400-meter individual medley, clocking 5:46.6.

Ruuska subsequently broke her own 400-meter record three times in 1958 and 1959, ultimately lowering the world mark to 5:40.2 on July 17, 1959.

At the 1960 Summer Olympics in Rome, Italy, Ruuska swam for the gold medal-winning U.S. team in the preliminary heats of the women's 4×100-meter freestyle relay.