Takeshi Hirayama (平山 雄, Hirayama Takeshi, January 1, 1923 – October 26, 1995) was a Japanese cancer epidemiologist and anti-tobacco activist who served as the chief of the epidemiology division at the in Tokyo from 1965 until 1985. He has been credited with publishing the first study linking passive smoking to lung cancer, and also conducted research on the relationship between certain dietary factors and cancer.