Philemon Thomas Herbert (November 1, 1825 – July 23, 1864) was a Democratic U.S. Representative from California. He represented the California Second District in the 34th Congress (1855–1857). He previously served two terms in the California State Assembly, representing Mariposa County. Herbert, born in Pine Apple, Alabama, was a combative "Southern gentleman". In 1856, when he was refused breakfast service at Willard's Hotel in Washington because it was too late in the morning, he got into a quarrel with the Irish headwaiter, and shot and killed him. He was acquitted of manslaughter by a sympathetic jury, but abandoned his Congressional career.
In 1859, he moved to El Paso, Texas, where he practiced law. When the Civil War broke out in 1861, he joined the Confederate Army. He rose to the rank of lieutenant colonel, and commanded the Arizona Cavalry and the Seventh Texas Cavalry Regiment. He was wounded at the Battle of Mansfield on April 8, 1864, and died of his wounds in July.