Thorius dubitus, commonly known as the Acultzingo pigmy salamander, is a species of salamander in the family Plethodontidae.

It is endemic to Mexico where it is found in the Sierra Madre de Oaxaca of west-central Veracruz and adjacent Puebla.

[2] Thorius dubitus is an exclusively terrestrial species.

[3] Its natural habitats are pine-oak cloud forests.

It is threatened by habitat loss caused by logging, livestock, and subsistence agriculture.