The Great Nicobar serpent eagle (Spilornis klossi), also known as the South Nicobar serpent eagle, is a species of bird of prey in the family Accipitridae.

It is probably the smallest known eagle, with a weight of about 450 g (0.99 lb), a wingspan of 85 to 95 cm (33 to 37 in) and a body length of about 38 to 42 cm (15 to 17 in).

[2][3] It is endemic to forest on the Indian island of Great Nicobar.

All major authorities now treat the Great Nicobar serpent eagle as a species, but in the past it was sometimes considered a subspecies of S. minimus.

Today S. minimus is either considered a subspecies of the crested serpent eagle or a monotypic species from the central Nicobar Islands, the Central Nicobar serpent eagle.