John McNeil (February 14, 1813 – June 8, 1891) was a general in the Union Army during the American Civil War. He was most noted for his role in the Palmyra Massacre and other acts of alleged brutality, as well as his participation in the Battle of Westport, the largest battle west of the Mississippi River. For his role in the Palmyra Massacre, he was given the nickname "Butcher of Palmyra".