The Ryan STs were a series of two seat, low-wing monoplane aircraft built by the Ryan Aeronautical Company. They were used as sportaircraft, as well as trainers by flying schools and the military of several countries.


T. Claude Ryan was the founder of the Ryan Aeronautical Company, the second incarnation of a company with this name, and the fourth company with which he had been involved to bear his name (the first, Ryan Airlines, was the manufacturer of the Ryan NYP, more famously known as the Spirit of St. Louis). He began the development of the ST (for "Sport Trainer", and also known as S-T), the first design of the company, in 1933.