William of Apulia (Latin: Guillelmus Apuliensis) was a poet and chronicler of the Normans, writing in the 1090s. His Latin epic, Gesta Roberti Wiscardi ("The Deeds of Robert Guiscard"), written in hexameters, is one of the principal contemporary sources for the Norman conquest of southern Italy, especially the career of Robert Guiscard, Duke of Apulia (1059–1085).