The Oaxacan small-headed rattlesnake, also known as Gloyd's small-headed rattlesnake, is a small species of snake found in the highlands of southern Mexico. Oaxacan small-headed rattlesnakes are often dark grey, sometimes purple or brownish, with jagged blotches of a darker color along the sides. A distinguishing feature of this snake is a black streak above the eye and a white streak below.

It occupies elevations from 1,000 - 3,000m above sea level, and can be found in a variety of habitats from tropical cloud forest, to dry pine-oak forests and even semi-arid deserts. This species is active during the day. It is an ambush predator, targeting mostly lizards of the genus Sceloporus (fence & scrub lizards), but occasional rodent and amphibian (toad) prey have been recorded.

Fun fact: This subspecies is named after American Herpetologist Howard K. Gloyd.