The 3rd Massachusetts Volunteer Cavalry Regiment was a cavalry regiment that served in the Union Army during the American Civil War. It was organized by consolidating the 41st Massachusetts Mounted Infantry and the 2nd Battalion Massachusetts Cavalry on June 17, 1863. The regiment served with the XIX Corps, Army of the Gulf during the Red River Campaign in 1864. Its heaviest combat during this campaign took place during the Battle of Sabine Crossroads.