Isaac Smith (1740 – August 29, 1807) was a physician, and a United States representative from New Jersey.

Born in Trenton, New Jersey, he graduated from Princeton College in 1755, was a teacher in that institution from 1755 to 1758, studied medicine, and commenced practice in Trenton.

In 1768 he was elected to the American Philosophical Society.

[1] He was a colonel in the Hunterdon County Militia in 1776 and 1777, serving with Lieutenant Colonel Abraham Hunt, and was elected as a Federalist to the Fourth Congress, serving from March 4, 1795 to March 3, 1797.

Smith was appointed by President George Washington a commissioner to treat with the Seneca Indians in 1797, and was an associate justice of the Supreme Court of New Jersey from 1777 to 1804.