Lake Weir is a fresh-water lake located in southern Marion County, Florida. Due to its large size and proximity, it is sometimes included with the Harris chain of lakes to the southeast, but is not directly hydrologically connected to them. It is connected to the west via a vegetation-filled canal to Little Lake Weir.

The lake was named for Nathaniel A. Ware, a state land official of the frontier period, but a misspelling of his