Fort Sill National Cemetery is a United States National Cemetery located in the city of Elgin in Comanche County, Oklahoma.

Administered by the United States Department of Veterans Affairs, it encompasses 391.3 acres (158.4 ha), and as of 2021 had more than 8,000 interments.

Fort Sill was established in 1869, in what was then Indian territory, by Major General Philip H. Sheridan, and named in honor of Brigadier General Joshua W. Sill, who died at the Battle of Stones River.

The area around Fort Sill served as a reservation for displaced Native American groups.

It is an expansion to the smaller 9-acre burial area located about ten miles south at Fort Sill.