William Fitzwilliam, 3rd Earl of Southampton (1701-1730) was an English nobleman known for his role in the political landscape of early 18th-century Britain. He inherited the title from his father, the 2nd Earl, and was a member of the Whig party, which was influential during his time. The 3rd Earl was also known for his connections to the Royal Family and his involvement in various social and political activities. He served as a Member of Parliament and was recognized for his contributions to the governance of England before his untimely death at the age of 29.