Isidore Albert Maria Smets (6 June 1901 – 31 May 1976) was a Belgian trade union leader and politician.
Born in Mechelen, Smets began working for the Union of Factory Workers when he was just sixteen years old, as secretary of its branch in his home town.
He also worked for the Union of Food and Hotel Workers, and for the local co-operative.
He fled to the United Kingdom during World War II, organising the Belgian trade unionist in exile in the country, and also broadcasting on behalf of the BBC.
After the war, he returned to Belgium, winning election as president of the General Union in 1949.