Nina Adams Harmer (born December 11, 1945), also known by her married name Nina Thompson, is an American former competition swimmer, two-time Olympian, and Pan American Games gold medalist.

Harmer was born in Philadelphia, Pennsylvania, and trained with the Vesper Boat Club in Philadelphia under Hall of Fame Coach Mary Freeman Kelly, who had started the program in 1955.

At the August 1961 Women's Swimming and Diving Championships in Philadelphia, she won both the 100 and 200-meter backstroke events, as well as swimming as a member of the 400-meter freestyle relay. On August 22, 1963, while swimming with the Vesper Boat Club, she lowered the National AAU record in the 100-yard backstroke a full second to 1:04.2 at the Badger Swim Club Water Carnival Meet in Larchmont, New York.

Summarizing her career, between 1961 and 1965 she won eight national swimming championships, consisting of four individual and four relays. By 1963, she had been a National AAU backstroke champion four times.

As a 14-year-old, she represented the United States at the 1960 Summer Olympics in Rome. She competed in the women's 100-meter backstroke, but did not advance beyond the preliminary heats. Swimming a 1:13.8, she had the 15th fastest time of all the preliminary swimmers.

At the 1963 Pan American Games in São Paulo, Brazil, she won the gold medal in the women's 100-meter backstroke.

In 1963, she graduated Springside Chestnut Hill Academy, an old and well-established Co-ed independent college preparatory day school in Chestnut Hill, Philadelphia, Pennsylvania. She married by the age of twenty. In August 1965, she demonstrated the Backstroke at the Badger Sports Club Water Carnival in Larchmont, New York, outside Mamaronek.

A year later at the 1964 Summer Olympics in Tokyo, Japan, Harmer swam for the gold medal-winning U.S. team in the preliminary heats of the women's 4×100-meter medley relay. She did not receive a medal under the 1964 international swimming rules because she did not swim in the relay event final.