Smith's mountain keelback (Opisthotropis spenceri), also known commonly as Spencer's stream snake,[2] is a species of snake in the family Colubridae.

[3] The preferred natural habitat of O. spenceri is flowing streams.

[2] O. spenceri may attain a total length (including tail) of 60 cm (24 in).

Ventrally it is yellowish white on the body, with gray mottling on the tail.

[2] O. spenceri preys upon freshwater shrimp, earthworms, fishes, frogs, and tadpoles.