The species is endemic to the Nicobar Islands of India.

[2] D. humayuni is a widely distributed species found in the central and southern Nicobar Islands, but absent from Car Nicobar.

The island of Chowra appears to be its northern range boundary, and Great Nicobar Island is its southern range boundary.

There is a single record of this species from Camorta Island of Nicobar collected by Wall.

D. humayuni is mostly confused with Dendrelaphis pictus andamanensis.