Girolamo Arnaldi (31 January 1929 – 30 January 2016) was an Italian historian. Born in Pisa, in 1951 Arnaldi graduated in Medieval History at the University of Naples, and then completed his postgraduate studied at the in the same city. He was professor of Medieval History at the University of Bologna from 1964 to 1970 and at the Sapienza University of Rome from 1970 to 1999. Between 1966 and 1970 he was president of the (ISIME) in Rome.