Theretra gnoma is a moth of the family Sphingidae described by Johan Christian Fabricius in 1775.

It is known from India, Sri Lanka, Myanmar, Nepal, Thailand, China.

The hindwing upperside has a pale marginal area which is more extensive than in T. c. clotho, nearly as broad as in T. c. celata.

Hindwing smoky black area is reduced than T. clotho, and paler towards anal angle and outer margin.

Ocellus on 4th somite is greenish, edged with yellow above, pink below with a lineal white center.