Maciej Rataj (19 February 1884 - 21 June 1940) was a Polish politician, president, socialist activist and writer. He was executed by Nazi Germany. Born in the Chłopy village near Lviv on 19 February 1884, he attended a gymnasium in Lviv and studied classical linguistics at the University of Lviv. Upon the completion of his studies he became a gymansium teacher first in Lviv, 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 PSL Piast and PSL Wyzwolenie political parties, and from 1931 a member of the Stronnictwo Ludowe. 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.
During both times he oversaw special election and appointed new governments.
In December 1940 he was arrested by Nazi Germany and executed in Palmiry during the German AB-Aktion operation in Poland.