Alexandra (Sasha) Lvovna Tolstaya (Russian: Александра Львовна Толстая; 18 July 1884 – 26 September 1979) was the youngest daughter and secretary of the noted Russian novelist Leo Tolstoy.

Although Alexandra Lvovna shared with her father the doctrine of non-violence, she felt it was her duty to take part in the events of World War I. For her courage, the Russian government awarded her three St George Medals and the rank of colonel.

The Bolsheviks imprisoned Alexandra in 1920, but she was installed as the director of the Tolstoy museum in Yasnaya Polyana the next year. She left the Soviet Union in 1929, and settled in the United States, where she founded the Tolstoy Foundation. She became a naturalized U.S. citizen in 1941.

In later years, she helped many Russian intellectuals (notably Vladimir Nabokov and Sergei Rachmaninoff) to escape Bolshevik persecution and to settle in America.