Gallimimus was ostrich-like, with a small head, toothless beak, large eyes, a long neck, short arms, long legs, and a long tail. It had a short 'hand' relative to the humerus length, when compared to other ornithomimids. The tail was used for balance. The eyes were placed on the sides of its head and the bottom front part of its beak was shaped like a shovel. Like most modern birds and other theropods, it had hollow bones. Gallimimus had a lot of traits that hint that it could run fast, such as a strong ilium, heavy tail base, long limbs, a long tibia and metatarsus and short toes, but no one knows how fast it could run.