Benjamin Weider, (1 February 1923 – 17 October 2008) was a Canadian soldier, author, historian (Napoleonic history), fitness proponent, benefactor of the arts, and entrepreneur. He co-founded the International Federation of BodyBuilders (IFBB) alongside his brother Joe Weider. The Weiders also founded many successful businesses including gyms, nutritional supplements and magazines such as Muscle & Fitness.
He wrote several books about Napoleon, including best seller The Murder of Napoleon, translated to 45 languages.
Benjamin Weider was born 1 February 1923 in the old Jewish immigrant quarter ("the Main") of Montréal (Quebec, Canada), the third son of Louis and Anna Weider, Polish Jewish emigrants from the town of Kurów (Poland). Ben left school at 13 to work in restaurants and factories.
In 1942, he enlisted in the Canadian Army, serving in the 6th Duke of Connaught's Royal Canadian Hussars, in which he did intelligence work as a member of the Canadian Intelligence Corps. Ben Weider served in the Canadian Army during World War II.
Weider and his brother, started a mimeographed magazine (Your Fitness) to promote weightlifting and sell exercise equipment, which expanded into other titles including Flex, Muscle & Fitness, Men's Fitness, and Fit Pregnancy. The magazines were sold in 2003 to American Media.
The brothers are attributed with creating bodybuilding as a sport, where the focus was on the form and fitness of the body shaped by the exercise. In 1965 the brothers formed the first Mr Olympia contest at the Brooklyn Academy of Music (New York City, New York, United States), an alternative to the Mr. Universe competition.
In 1968, the brothers brought Arnold Schwarzenegger, who was then an unknown Austrian bodybuilder, to California.
He co-founded the International Federation of BodyBuilding & Fitness (IFBB) along with brother Joe Weider, and was its president until he announced his retirement on 29 October 2006. He also co-founded (1936) and ran a physical fitness and sporting goods business from Montreal with his brother, which bears their family name.