Thomas Fitzwilliam, 5th Earl of Southampton (1743–1793), was a British nobleman known for his role in the House of Lords. He inherited the title from his father, Thomas Fitzwilliam, 4th Earl of Southampton, and was involved in various political and social activities during his lifetime. The 5th Earl was also a patron of the arts and contributed to the cultural landscape of his time. He was associated with notable figures, including William Hogarth, and his estate played a role in the development of the Southampton area.