John Walker (13 February 1744 - 2 December 1809) was an American politician.

Walker was born in Virginia in 1744. He received private education before attending the College of William and Mary, which he graduated from in 1764. He served in the Continental Army as an aide to George Washington, holding the rank of colonel. In 1790, he served as a delegate to the Continental Congress. He then studied law. When William Grayson died in 1790, Walker was appointed to the United States Senate to serve from 31 March to 9 November of that year, when a successor was elected by the state legislature. Walker died in 1809.