Júlio Afrânio Peixoto (born December 17 1876 in Lençóis – January 12, 1947) was a Brazilian physician, writer, politician, historian, university president, and pioneering eugenicist.
He married Francisca de Faria, in 1912, and they had one child, a son, "Juquinha" ("Little Juca"), who was both mentally ill and of poor physical health and who died in 1942.
Afrânio Peixoto was a student and follower of Juliano Moreira, who initiated the scientific treatment of mental illness in Brazil and who invited his young protégé to Rio de Janeiro.
He was important in establishing the foundations of workers' health when he took the chair of forensic medicine in both the medical and law schools in Rio de Janeiro in 1907.
From his pioneering studies of occupational risks and job-related accidents and diseases, many publications were released, and legal safety nets were finally established for Brazilian workers.
Afrânio Peixoto used his influence and prestige to dispute Carlos Chagas' clinical and parasitological findings and to transfer credit for the discovery of the trypanosome to Oswaldo Cruz, much to the disadvantage of everyone concerned.