Pierre Laget (July 11, 1885 – September 1, 1944) was a French dentist, convicted murderer and suspected serial killer who fatally poisoned his wife and later attempted to kill his younger sister between December 1929 and February 1930. Although he was also suspected of killing his first wife and aunt in 1922 and 1923, he was convicted for the latter crimes and sentenced to death, but his sentence was later commuted by President Paul Doumer. While serving his new sentence in prison, he committed suicide in September 1944.