William Fitzwilliam, 5th Earl Fitzwilliam (1780-1833), was a British nobleman and politician. He inherited the title from his father and became known for his significant contributions to the Whig Party. Fitzwilliam served as a Member of Parliament and was involved in various social and political reforms during his lifetime. Fitzwilliam was also a prominent landowner, managing extensive estates in Yorkshire and Ireland. He was known for his philanthropic efforts, particularly in education and agriculture, and played a role in the development of local communities. His legacy includes a commitment to social improvement and responsible land stewardship.