Gamaliel Henry Barstow (July 20, 1784 – March 30, 1865) was a physician, an American politician, a judge, and a U.S. representative for New York.

He married Nancy Coryell and they had three children, Elijah, Mary, and John.

He studied medicine in Great Barrington, Massachusetts In 1812, Barstow moved to Tioga County, and there worked at his father's farm and taught school.

He then built the first frame house in the town of Nichols, and opened a store at this location.

Afterward, he continued the practice of medicine and engaged in agricultural pursuits in Nichols, New York, where he died on March 30, 1865, aged 80.