Adolf "Adi" Dassler (born 3 November 1900 in Herzogenaurach, Kingdom of Bavaria, German Empire; died 6 September 1978 in Herzogenaurach, West Germany) was the founder of the German sportswear company Adidas and the younger brother of Rudolf Dassler, founder of Puma.

Trained as a cobbler, Adi Dassler started to produce his own sports shoes in his mother's laundry after his return from World War I. His father, Christoph, who worked in a shoe factory, and the Zehlein brothers, who produced the handmade spikes for track shoes in their blacksmith's shop, supported Dassler in starting his own business. On 1 July 1924, his older brother Rudolf Dassler joined the business, which became the Gebrüder Dassler Schuhfabrik (Dassler Brothers Shoe Factory).

At the 1928 Olympics, Dassler equipped many athletes, laying the foundation for the international expansion of the company. During the 1936 Summer Olympics in Berlin, Dassler equipped Jesse Owens of the USA with his shoes. Jesse Owens won 4 gold medals in the year he wore Adi's shoes.

With the rise of Adolf Hitler in the 1930s, both Dassler brothers joined the Nazi Party, with Rudolf reputed as being the more ardent National Socialist. Rudolf was drafted, and later captured, while Adi stayed behind to produce boots for the Wehrmacht and then broke away from the Nazi Party. The war exacerbated the differences between the brothers and their wives. Rudolf, upon his capture by American troops, was suspected of being a member of the SS, information supposedly supplied by none other than his brother Adi.

By 1948, the rift between the brothers widened. Rudolf left the company to found Puma on the other side of town (across the Aurach River), and Adolf Dassler renamed the company Adidas after his own nickname. (Adi Dassler).

In 1973, Adolf Dassler's son Horst Dassler founded Arena, a producer of swimming equipment. After Adolf Dassler's death in 1978, Horst and his wife Käthe took over the management. Horst died nine years later, in 1987. Adidas was transformed into a private limited company in 1989, but remained family property until its IPO in 1995.

In 2006, a sculpture of Adolf Dassler was opened up in the Adi-Dassler-Stadium in Herzogenaurauch. It was created by the artist Josef Tabachnyk.