| Named By: | Xu Xing and Wang Xiaolin in 2003 |
| Time Period: | Early Cretaceous, 122 Ma |
| Location: | China, Liaoning |
| Size: | Estimated at possibly up to one meter long |
| Diet: | Uncertain. Possibly an Insectivore |
| Fossil(s): | The forelimbs, shoulder, some ribs, gastralia and feathers are all that are so far known |
| Classification: | | Chordata | Reptilia | Dinosauria | Saurischia | Theropoda | Tetanurae | Coelurosauria | Maniraptora | |
Yixianosaurus (meaning "Yixian lizard") is a maniraptoran theropod dinosaur genus from the Early Cretaceous of China.
The type species, Yixianosaurus longimanus, was formally named and described by Xu Xing and Wang Xiaolin in 2003. Its partial skeleton was discovered in 2001, in Liaoning at Wangjiagou in northeastern China. The generic name refers to the Yixian Formation. The specific name means "with a long hand" from Latin longus, "long", and manus, "hand".
Yixianosaurus is known only from a single specimen, holotype IVPP V12638, which likely derived from the Dawangzhangzi Bed (early Aptian stage, 122 million years ago). It is a compression fossil, preserved on a single slab, that, however, has been sawed into several pieces. It consists of the shoulder girdle together with a pair of fossilized arms complete with fossilized feathers and some ribs and gastralia. Yixianosaurus has a very long hand, 140% of the length of the 89 millimetres (3.5 in) long humerus. The second finger is the longest. The fingers bear large and recurved claws. The feathers are not preserved well enough to show a specific structure, but they appear similar to the contour feathers of some Yixian Formation birds. The large hands could have served in catching prey or assisted climbing. The total body length has been estimated at 1 metre (3.3 ft), the weight at 1 kilogram (2.2 lbs).