Philip Henry Stanhope, 4th Earl Stanhope FRS, was an English aristocrat, chiefly remembered for his role in the Kaspar Hauser case during the 1830s.

Kaspar Hauser was a German youth who claimed to have grown up in the total isolation of a darkened cell. Hauser's claims, and his subsequent death from a stab wound, sparked much debate and controversy. Theories propounded at the time identified him as a member of the grand ducal House of Baden, hidden away because of royal intrigue. These opinions may or may not have been documented by later investigations. Other theories proposed that Hauser had been a fraud.