The introduction of arthroscopic surgery is to be considered one of the key technological advances in twentieth-century orthopedic surgery. Its origins lie in early endoscopy, beginning with Bozzini’s Lichtleiter more than 200 years ago. In 1912, the first results on endoscopy of the knee joint were presented by Nordentoft in Berlin. Until after the Second World War, smaller arthroscopes were developed, and the first illustrated arthroscopic findings were published. It was Watanabe, the father of modern arthroscopy, who developed his Watanabe No. 21 arthroscope in 1959, the first mass-produced model. He inaugurated the principle of triangulation, removed the first tumor arthroscopically, and published the first Atlas of Arthroscopy. Further innovations included, among others, motorized shaver instruments, rod lenses, fiber-optic cold light, improved visualization, and 30° forward oblique arthroscopes, while almost every joint may be accessed. While teaching the art of arthroscopy began at first one-on-one, professional societies were founded in the 1970s, fostering education and global growth. While ridiculed in its early days, arthroscopy today is a standard minimally invasive technique for diagnosis and treatment across multiple joints.