Friedrich Wolfgang Adler (July 9, 1879 – January 2, 1960) was an Austrian politician, lobbyist and revolutionary. He is perhaps best known for his assassination of Count Karl von Stürgkh in 1916.
Adler was born in Vienna, the son of social democratic politician Victor Adler. He studied chemistry, physics and mathematics in Zurich. In 1897 he became a member of the Social Democratic Party of Austria (SPÖ) and from 1907 was editor of the magazine Der Kampf. He was a good friend of Albert Einstein.
Adler was engaged in the international trade union movement and in 1911 he gave up his scientific activities to become the secretary-general of the SPÖ in Vienna, an office he held until 1914. He became the spokesperson of the left wing of the party and after the start of the First World War he agitated particularly against the SPÖ's policy of supporting the war.
In his fight against the war policy of Austria-Hungary Adler resorted to drastic measures. On October 21, 1916, in the dining room of the Viennese hotel Meißl und Schadn, he shot the Minister-President of Austria Count Karl von Stürgkh three times with a pistol, killing him. For his crime Adler was sentenced to death, a sentence which was commuted to 18 years imprisonment.
After the outbreak of the revolution of 1918 he was released and played a significant role as the leader of the Arbeiterräte (workers' councils) and as a member of the National Council of Austria. From the mid-1920s he was primarily active in the Socialist International, serving as secretary-general for over 15 years.
After the outbreak of the Second World War Adler fled to the United States. In 1946 he retired from politics and edited his father Victor's exchange of letters with August Bebel and Karl Kautsky.
Adler died on January 2, 1960 in Zurich.