The name Willy is a diminutive form of the Germanic name William, which is derived from the Old German words "wil" meaning "will" or "desire" and "helm" meaning "helmet" or "protection." The name William was brought to England by the Normans after their conquest in 1066, and it became popular among the nobility and upper classes.

Willy emerged as a nickname or shortened version of William, particularly in the Middle Ages and Renaissance period. It was commonly used as an informal or affectionate form of the name, often among family members or close friends. The spelling "Willy" is believed to have originated in English-speaking countries, although variations such as "Willie" and "Willi" exist in other languages.

One of the earliest recorded instances of the name Willy can be found in the 14th-century literary work "The Canterbury Tales" by Geoffrey Chaucer, where the character "Willy" is mentioned. During the Renaissance period, the name Willy gained popularity among artists and writers, including the Dutch painter Willy Sluiter (1873-1949) and the English poet Willy Muir (1890-1979).

In the 18th and 19th centuries, several notable figures bore the name Willy. Among them were Willy Brandt (1913-1992), a German statesman and former Chancellor of West Germany, and Willy Wonka, the fictional character from Roald Dahl's beloved children's book "Charlie and the Chocolate Factory" (1964).

Other famous individuals with the first name Willy include Willy Messerschmitt (1898-1978), the German aircraft designer and engineer, Willy Russell (born 1947), the English playwright and author, and Willy Tybur (1887-1952), a Dutch Olympic cyclist who won multiple gold medals in the early 20th century.

While the name Willy may have fallen out of fashion in some regions, it remains a cherished nickname and a nod to the rich history and cultural significance of the name William.