John Roderigo Dos Passos (January 14, 1896 – September 28, 1970) was an American novelist and artist.
Dos Passos was born in Chicago, Illinois, the illegitimate son of John Randolph Dos Passos (1844–1917). The elder Dos Passos was a lawyer of Madeiran Portuguese descent, married to Mary Hays, with whom he already had a son Louis Hays Dos Passos, several years older than Dos Passos. He was an authority on trusts and a staunch supporter of the powerful industrial conglomerates his son would come to oppose in his fictional works of the 1920s and 30s. In 1910, following the death of his first wife, the elder Dos Passos was able to marry his mistress (and John Dos Passos' mother), Lucy Addison Sprigg Madison, from Petersburg. Although he provided for his son's schooling, he refused to acknowledge him until two years after his marriage (when his son was 16).
The younger Dos Passos received a first-class education, enrolling at The Choate School (now Choate Rosemary Hall) in Wallingford, Connecticut in 1907 under the name John Roderigo Madison, then traveling with a private tutor on a six-month tour of France, England, Italy, Greece, and the Middle East to study the masters of classical art, architecture, and literature.