Irwin Suall (1925–1998) was an American socialist and researcher. He was national director of fact-finding for the Anti-Defamation League from 1967 to 1997 in which capacity he directed that organization's undercover intelligence gathering on extremist groups.
Born in 1925 on the Lower East Side to immigrant parents, Suall grew up in Brownsville, Brooklyn, and graduated from Samuel Tilden High School. After briefly attending Brooklyn College, Suall joined the Merchant Marines in 1945, for three years. While a Merchant Marine, he visited Jewish refugees from Nazi-occupied Europe living in squalor in Shanghai. This experience left an indelible impression on him. After his stint in the Merchant Marines, Suall studied at Ruskin College, Oxford on a Fulbright scholarship. He graduated with a BA in political science in 1950.
Suall was always politically minded, joining the Young Peoples Socialist League as a teenager. When he returned to the U.S. after studying in England, he did brief stints as head of public relations for the Jewish Labor Committee, education director for the International Ladies Garment Workers Union and national secretary for the Socialist Party–Social Democratic Federation. In the latter capacity, he was instrumental in convincing Norman Thomas and others to allow individual members of the Independent Socialist League, sometimes known as Shatchmanites, to join with the party. During that period, Suall was ejected from the Soviet consulate in New York when he and William Lusk tried to present a protest to Arkady Sobolev, the USSR's representative to the United Nation's. They were protesting the execution of Imre Nagy, Nicolas Gimes and other Hungarians.
In 1957, Suall replaced Herman Singer as Executive Secretary of the Socialist Party of America. He would remain in that role until 1968. The Arab–Israeli 1967 Six-Day war had a profound effect on him. He visited Israel shortly thereafter and returned to the U.S. "a changed man" according to ADL head Abraham Foxman. His attitude towards socialism apparently changed, and he "began to realize that his efforts on behalf of democracy and human dignity were part of a larger Jewish struggle". He became fact-finding director of the ADL that year and his work "reinforced his growing awareness of the intimate linkages between extremism, totalitarianism, and anti-Semitism".