Avimimus was originally suggested to be a very close relative of birds, given its unique suite of bird-like features not known in other dinosaurs at the time.
In fact, Kurzanov argued that Avimimus, rather than the famous early bird Archaeopteryx, was close to the direct ancestor of modern birds, and that Archaeopteryx was not as closely related to birds as had previously been suggested.
However, this view has not been supported by later phylogenetic analyses of dinosaur and bird relationships.
Most modern scientists find that Avimimus in fact belongs to a diverse group of bird-like dinosaurs more primitive than Archaeopteryx, the oviraptorosaurs.

 
Kurzanov placed Avimimus in its own family, Avimimidae, in 1981.
In 1991, Sankar Chatterjee erected the Order Avimimiformes to include Avimimus.
Neither of these group names is used frequently by paleontologists as they include only a single species.
More recent studies have shown that Avimimus is best grouped within the Oviraptoridae, within the subgroup Elmisaurinae.

The following cladogram follows an analysis by Phil Senter, 2007.
Avimimus was originally suggested to be a very close relative of birds, given its unique suite of bird-like features not known in other dinosaurs at the time. In fact, Kurzanov argued that Avimimus, rather than the famous early bird Archaeopteryx, was close to the direct ancestor of modern birds, and that Archaeopteryx was not as closely related to birds as had previously been suggested. However, this view has not been supported by later phylogenetic analyses of dinosaur and bird relationships. Most modern scientists find that Avimimus in fact belongs to a diverse group of bird-like dinosaurs more primitive than Archaeopteryx, the oviraptorosaurs.
 
Kurzanov placed Avimimus in its own family, Avimimidae, in 1981. In 1991, Sankar Chatterjee erected the Order Avimimiformes to include Avimimus. Neither of these group names is used frequently by paleontologists as they include only a single species. More recent studies have shown that Avimimus is best grouped within the Oviraptoridae, within the subgroup Elmisaurinae.
The following cladogram follows an analysis by Phil Senter, 2007.
Avimimus