Meaning A boy's name of Spanish origin, it means "Variant of William 'Resolute protector'." Origin of Gillermo Spanish +-100%Zoom level changed to 1 Popular Middle Names Pronunciation 🔊 Listen Gillermo Similar Names Gwilym Gwylim Guillaume Bill Willy Guglielmo Wilkes Willard Wim Oddmund Year by Year Popularity of Gillermo