Cassida denticollis is a species of leaf beetle, situated in the subfamily Cassidinae (tortoise beetles) and the genus Cassida, found in Mongolia, West China (Xinjiang province), and the Western Palaearctic region.

[1] Cassida denticollis, like all species of Cassida has its head covered by the pronotum and wide elytral margins.

It measures 5.1–7.0 mm in length, is green in colour with brownish-red areas around the scutellum.

It has a distinct tooth at the rear edge of the pronotum, and a series of small, strong, blunt teeth on the front edges of the elytra from which this species derives its name.

[2] The species feeds on plants from the family Asteraceae, including Achillea millefolium, Artemisia absinthium, Artemisia campestris and various plants Tanacetum species, including Tanacetum corymbosum and Tansy.