Harry Kendall Thaw (February 12, 1871 – February 22, 1947) was the son of American coal and railroad baron William Thaw Sr. Heir to a multimillion-dollar fortune, the younger Thaw is most notable for murdering the renowned architect Stanford White in front of hundreds of witnesses at the rooftop theatre of New York City's Madison Square Garden on June 25, 1906.

Thaw had harbored an obsessive hatred of White, believing he had blocked Thaw's access to the social elite of New York. White had also had a previous relationship with Thaw's wife, the model and chorus girl Evelyn Nesbit, when she was age 16 or 17, which had allegedly begun with White plying Nesbit with alcohol (and possibly drugs) and raping her while she was unconscious. In Thaw's mind, the relationship had "ruined" her. Thaw's trial for murder was heavily publicized in the press, to the extent that it was called the "trial of the century". After one hung jury, he was found not guilty by reason of insanity.

Plagued by mental illness throughout his life that was evident even in his childhood, Thaw spent money lavishly to fund his obsessive partying, drug addiction, abusive behavior toward those around him, as well as the gratification of his sexual appetites. The Thaw family's wealth allowed them to buy the silence of anyone who threatened to make public the worst of Thaw's reckless behavior and licentious transgressions. However, he had several additional serious confrontations with the criminal justice system, one of which resulted in seven years' confinement in a mental institution.