Esther Stroy (born August 12, 1953) is a former American track and field athlete, who competed in the sprinting events. She is best known for competing at the 1968 Olympics in the 400-meter dash as a 15-year-old, the youngest competitor at those games.

Esther Stroy was only 15 years and 64 days old when she competed at the 1968 Olympics.

In 2012, Stroy, now Esther Stroy-Harper, remembered it as being "more than the world's best summer vacation. It was the opportunity of a lifetime".

In the 400 m event itself, she reached the semi-final but injured herself whilst leading the race and finally finished fifth so therefore not qualifying for the final. Her Olympic misfortune was repeated in 1972. As Stroy-Harper recalls “Right before the 1972 Olympics, I injured that same hamstring, so I didn't make the team. I went to Munich, but as a spectator.”

In the 1968 United States Olympic Trials, Stroy was third in the 400 m event and was entered but did not compete in the 200 m. In 1972, she was third in her heat of the 200 m and was entered but did not compete in the 400 m.

Between the two Olympics, she continued running for her universities and country.

The high point of her career was winning gold at the 1971 Pan American Games in the 4 x 400 meter relay and bronze in the 200 meters. She also won the 220 yards dash at the 1971 and 1972 AAU Indoor Championships.

In 1971, she was a member of a 4 x 1-mile women's relay team that set a new world record at a USA versus Pan-Africa meet.