Romeo Montague and family, characters in Shakespeare's "Romeo and Juliet"
Duck the Great Western Engine aka Montague, an engine from TV's "Thomas and Friends"
Montague the Mouse, character from TV's "Johnny Test"
Montague Egg, detective in series by Dorothy L. Sayers
Montague "Monty" Bodkin, character in P. G. Wodehouse novels
Montague Brewster, main character in movie "Brewster's Millions"
Montague "Monty" D'Ysquith Navarro, main character in the Broadway musical, "A Gentleman's Guide to Love and Murder"