Polyptychus dentatus is a moth of the family Sphingidae. It is known from Sri Lanka, tropical India and tropical Pakistan. The wingspan is 92–120 mm. The forewing upperside ground colour is grey-brown with darker brown transverse lines. The antemedian, postmedian and submarginal lines are well-developed and almost straight. The median line is sinuous and inconspicuous. There is a strongly serrate line present between the postmedian and submarginal lines.