Henry Andrew "Heck" Thomas (January 3, 1850 – August 14, 1912) was a lawman on the American frontier, most notably in Indian Territory. He was known for helping bring law and order to the region. In 1889 as a deputy in Fort Smith, Arkansas, he tried to capture Ned Christie (Cherokee), wanted as a suspect in the killing of a US marshal.

Thomas was among the lawmen who ended the run of the Wild Bunch, also known as the Doolin-Dalton Gang. Emmett Dalton, the surviving member of the gang, said that due to Thomas's relentless pursuit, they attempted two simultaneous robberies in Coffeyville, Kansas, planning to leave the territory with a haul. These failed and four gang members died in a shootout there. In August 1896, Thomas led a posse that tracked down and killed outlaw Bill Doolin.