Geophis sanniolus, commonly known as the pygmy snail-eating snake or the pygmy snail sucker, is a species of small snake in the subfamily Dipsadinae of the family Colubridae. The species is native to Central America and southeastern Mexico.
Geophis sanniolus is found in Belize, Guatemala, and the Mexican states of Campeche, Quintana Roo, and Yucatán.
Geophis sanniolus is a relatively common snake that occurs in tropical semi-deciduous forest and thorn forest, and also in degraded forest.
An oviparous species, Geophis sanniolus reaches sexual maturity in eight months and produces a single clutch per year.
Two subspecies are recognized as being valid, including the nominotypical subspecies.
Nota bene: A trinomial authority or a binomial authority in parentheses indicates that the subspecies or species was originally described in a genus other than Geophis.
The subspecific name, neilli, is in honor of American herpetologist Wilfred T. Neill.