The Ceratolasmatidae are a family of harvestmen with eleven described species.

The monophyly of this family is questionable; it is composed of three possibly monophyletic groups:[1] The family is restricted to North America, from California to British Columbia.

Crosbycus is also found in Eastern Asia.

[1] The genus name is a combination of Ancient Greek keras "horn" and the ending -lasma, referring to the similarity of genera such as Ortholasma and Dendrolasma (Nemastomatidae).

[1]