Ignacy Mo?cicki (born Dec. 1, 1867, Mierzanow, Pol., Russian Empire [now in Poland]?died Oct. 2, 1946, Versoix, Switz.) was a Polish statesman, scholar, and scientist, who, as president of the Polish republic, was a supporter of the dictatorship of Jozef Piłsudski.

Mo?cicki was educated as a chemist. He joined the Polish Socialist Party in the early 1890s and was involved in an attempt on the life of the governor-general of Warsaw . Sought by the Russian police for that involvement, Mo?cicki fled to England (1892), where he met Piłsudski.

Returning to the European continent, in 1897 Mo?cicki began to teach at the Roman Catholic university in Fribourg, Switz. In 1912 he was given the professorship of electrochemistry at the University of Lemberg (Polish: Lwow). After World War I Mo?cicki served the new Polish state by restoring synthetic nitrogen production at Krolewska Huta (now Chorzow), Upper Silesia, at a plant that had been stripped by the Germans.

After the Piłsudski coup d’etat in May 1926, Mo?cicki was elected as president of the republic in June, in which post he served Piłsudski faithfully. He served another term as president from 1933. Following Piłsudski’s death in 1935, Mo?cicki’s politics became much more liberal. After the German and Soviet occupation of Poland in September 1939, Mo?cicki fled to Romania , where he was interned briefly, and thence to Switzerland , where he resided until his death.