William Vandever (March 31, 1817 – July 23, 1893) was a United States representative from Iowa and later from California, and a general in the Union Army during the American Civil War.

He joined up with William T. Sherman's army in command of the 3rd Brigade, 2nd Division, XVI Corps and fought at the battles of Kennesaw Mountain, Atlanta and Ezra Church.

Although his official congressional biography states that Vandever only served in Congress until September 24, 1861 (early in his second term), he never resigned his seat.

In May 1862, Democratic Congressman George H. Browne of Rhode Island raised a challenge to the constitutionality of Vandever holding a military commission and commanding a regiment while remaining a member of Congress, but consideration by the House on that issue was deferred until December 1862.

[3] He resumed the practice of law in Dubuque and was appointed United States Indian inspector by President Ulysses S. Grant in 1873, and served until 1877.