Trilasma is a genus of harvestmen in the family Nemastomatidae with nine described species (as of 2023).

They revised numerous samples of most species of several Ortholasmatinae in a broad revision, except the troglobiont Ortholasma sbordonii Šilhavý, 1974 which was redescribed from just the original type material.

[7] The same revised list of species were include in catalog by Schönhofer (2013).

[8] The genus Trilasma was revised as a subgenus of Ortholasma by Shear and Gruber, 1983.

[6] However, it was then again diagnosed as distinct from Ortholasma by several aspects, such as the median hood arising dorsally with an anterior projection in a shallow curve.