David Campbell Humphreys (November 9, 1817 – July 12, 1879) was a United States federal judge.
Born in Morgan County, Alabama, Humphreys began the practice of law in Madison County, Alabama. He was a member of the Alabama House of Representatives in 1843, 1849, 1853, and 1868. He was a planter and in private practice in Huntsville, Alabama from 1850 to 1861. During the Civil War, he served in the Confederate Army, rising to the rank of Colonel.
On April 22, 1870, Humphreys was nominated by President Ulysses Grant to a seat as an associate justice of the Supreme Court of the District of Columbia vacated by George P. Fisher. Humphreys was confirmed by the United States Senate on May 10, 1870, and received his commission on May 13, 1870. In 1873, President Ulysses S. Grant nominated him to be United States District Judge for the three districts of Alabama, in an effort to replace the increasingly unpopular Richard Busteed with an Alabama native (Busteed was simultaneously nominated to take Humphreys' seat in the District of Columbia), but the nomination was returned by Senate as irregular.
Humphreys remained on the District of Columbia court until his death, in 1879, in Fairfax County, Virginia.