Cryptophis nigrostriatus, also known as the black-striped snake, is a species of venomous snake native to Australia and New Guinea. The specific epithet nigrostriatus ("black-striped") refers to its body markings.
The snake is slender and grows to an average of about 50 cm in length. The upper body is reddish-brown to pink, with a black, full-length vertebral stripe and dark head.
The species is viviparous, with an average litter size of six.
The species occurs in the southern Western Province of Papua New Guinea, and in Australia from the northern Cape York Peninsula south-eastwards through eastern Queensland to Rockhampton. It inhabits dry woodlands. The type locality is near Rockhampton.