Gertrude Lamson (October 8, 1874 – February 7, 1965), known professionally as Nance O'Neil or Nancy O'Neil, was an American stage and film actress who performed in plays in various theaters around the world but worked predominantly in the United States between the 1890s and 1930s. At the height of her career, she was promoted on theater bills and in period trade publications and newspapers as the "American Bernhardt".