Maria Janitschek née Tölk (July 22, 1859 in Mödling (near Vienna) - April 28, 1927 in Munich) was a German writer of Austrian origin.

Born the illegitimate child of a military officer, she was raised by her mother Anna Tölk in impoverished circumstances and educated in a Hungarian convent school.

When she was 19, she moved with her mother to Graz where she published her first articles as a journalist under the pseudonym Marius Stein.

Germany banned her short story collection Die neue Eva in 1909.

She considered Émile Zola, Henrik Ibsen, and Leo Tolstoy to be her role models.