Stewart Leonard Van Vliet (July 21, 1815 – March 28, 1901), was a United States Army officer who fought on the side of the Union during the American Civil War.

In September 1855, he served in the Sioux Expedition under Col. William S. Harney, and in 1857, with Col. Albert Sidney Johnston in the Utah War against the Mormons.

He made a rapid thousand-mile drive from Leavenworth to Salt Lake City, traveling with his escort of thirty soldiers, in light wagons.

He was so much impressed by these warnings that he left his little force 150 miles from Salt Lake City, in order not to endanger their lives, and rode into the Mormon stronghold alone.

His appointment to brigadier general expired a week later, and he was stationed in New York City for the remainder of the war, coordinating supplies and transportation for troops in the field.