Elymus macgregorii, also known as early wildrye and Macgregor's wildrye, is a species of grass found in North America, usually east of the 100th meridian. It hybridizes readily with Elymus virginicus and Elymus hystrix.
Elymus macgregorii is a perennial, facultative wetland species that grows about tall.
It is often found alongside sugar maple, white ash, and American linden. It flowers and fruits from mid-May to late June.