37655 Illapa (provisional designation ) is a carbonaceous asteroid, classified as near-Earth object and potentially hazardous asteroid of the Apollo group, approximately 1.5 kilometers in diameter. It was discovered, on 1 August 1994, by American astronomer couple Carolyn and Eugene Shoemaker at the Palomar Observatory in California, United States.
On 16 August 2003, Illapa made a close approach to Earth of .
Illapa has an estimated diameter of 0.8 to 1.8 kilometers for an assumed geometric albedo between 0.20 and 0.04. For an assumed albedo of 0.057, which is typical for carbonaceous C-type asteroids, and an absolute magnitude of 17.9, the asteroid has a calculated mean diameter of 1.5 kilometers. The body has a short rotation period of 2.6556 hours.
This minor planet was named after Illapa (Apu Illapu), the thunder or weather god from Inca mythology.