William Claiborne (c. 1600 – c. 1677) (also spelled William Clayborne) is an English pioneer, surveyor, and an early settler in Virginia and Maryland.

Claiborne becomes a wealthy planter, a trader, and a major figure in the politics of the colony.

He is a central figure in the disputes between the colonists of Maryland and of Virginia, partly because of his trading post on Kent Island in the Chesapeake Bay, which provokes the first naval battles in North American waters.

Claiborne repeatedly attempts and fails to regain Kent Island, sometimes by force of arms, after its inclusion in the lands that are granted by a royal charter to the Calvert family, thus becoming Maryland.

A puritan, Claiborne sides with Parliament during the English Civil War and is appointed to a commission charged with subduing and managing the Virginia and Maryland colonies.

He plays a role in the submission of Virginia to Parliamentary rule in this period.

Following the restoration of the English monarchy in 1660, he retires from involvement in the politics of the Virginia colony.

He dies around 1677 at his plantation, Romancoke, on Virginia's Pamunkey River.