Maciej Rataj (19 February 1884 – 21 June 1940) was a Polish politician and writer.
Born in the village of Chłopy near Lwów (now Lviv, Ukraine) on 19 February 1884, he attended a gymnasium in Lwów and studied classical linguistics at the University of Lwów. Upon the completion of his studies he became a gymnasium teacher first in Lwów, and later in Zamość.
He became involved in politics after the Second Polish Republic gained independence following the First World War. He was a member of the Polish People's Party "Piast" political party, and from 1931 a member of the People's Party. He became president of the Stronnictwo and the chief editor of the party's official paper, the 'Zielony Sztandar' in 1935. From 1919 to 1930 and from 1934–1935 he was a member of parliament for the Sejm (Polish Parliament), and from 1922 to 1928 he was the Marshal of the Sejm. Between 1920–1921 he was the Minister of Religion and Public Education, and took part in work on the March Constitution.
He was President of Poland twice: first in December 1922 after the assassination of president Gabriel Narutowicz as Acting President of the Republic of Poland for one week, and again in May 1926, after Józef Piłsudski's May Coup and the resignation of president Stanisław Wojciechowski. His second term lasted half of a month.