Polyptychus dentatus, the straight-lined crenulate hawkmoth, is a moth of the family Sphingidae.

It is known from Sri Lanka, tropical India and tropical Pakistan.

In India, larvae have been recorded on Cordia dichotoma, Cordia sebestena and Ehretia laevis.

Mature larvae are about 100 mm long.

This Smerinthini-related article is a stub.