Sinornithoides, meaning “Chinese bird form,” is a genus of theropod dinosaur from the Barremian stage of the Early Cretaceous Period (130 to 125 million years ago). The type species, S. youngi, was described in 1993 by Dale Russell and Dong Zhiming based on a fossil found in the Ejinhoro Formation.
It is known from a nearly complete specimen, missing only the roof of the skull and the cervical and dorsal vertebrae, along with a few other skeletal fragments. The holotype was preserved in a roosting position with its snout tucked under its left hand.
An adult Sinornithoides measured about 3 feet long. The species lived in Inner Mongolia, China and most likely ate invertebrates and other small prey.