The William Barnwell House is a historic Building in Beaufort, South Carolina and is a part of the Beaufort Historic District. It was built in 1816 by the critically acclaimed Gibbes Brothers for their sister, Sarah Reeve Gibbes. The property got its name from her husband, though, William Wigg Barnwell, who came from the prominent Beaufort family connected to Major William Hazzard Wigg, a Revolutionary War hero.

The William Barnwell House stayed with the Barnwells until 1895. It was then when the property was given to the city. The local government then used it as a schoolhouse, and then transformed it to an apartment building before shutting it down for disrepair. It was then rescued by the Historic Beaufort Foundation in 1973 from threats of demolition.

The William Barnwell House is now owned by the antiques dealer, Jim Williams.