Sandra Lynn Neilson (born March 20, 1956), also known by her married name Sandy Bell, is an American former competition swimmer, three-time Olympic gold medalist, and former world record-holder.

While a student at El Monte High School, Neilson set CIF Southern Section records in 1972 for both the 50-yard and 100-yard freestyle events.

[1] She later attended University of California, Santa Barbara, where she was a member of the UCSB Gauchos swim team and a three-time All-American.

Despite being ranked as the third-best American swimmer, Neilson participated in the 1972 Summer Olympics in Munich, Germany at the age of 16.

In the 100-meter freestyle, Neilson defeated heavy favorites Shane Gould from Australia and her American teammate Shirley Babashoff in an Olympic record time of 58.59 seconds.