William Barnett House is a historic home located at Alleghany Springs, Montgomery County, Virginia. It is a long two-story, log and frame structure consisting of a number of elements of different dates. The earliest section may date to 1813, and is the central log section with a two-story frame or log addition and adjacent room and a frame two-room section added in the mid-19th century. It has a rear wing and is topped by a standing seam metal gable roof. It features a two-story ornamental porch that spans the entire front of the building with chamfered posts and sawn balusters. Also on the property are a contributing two-story, single-pen log kitchen; a small stone shed-roofed greenhouse; and a corn crib.

It was listed on the National Register of Historic Places in 1989.