- Actor-Inspired Element: The line "I think we only use ten percent of our hearts" was an idea by Owen Wilson.
- Cast the Runner-Up: Will Ferrell turned down the role of John in favor of the smaller role of Chazz.
- Dyeing for Your Art: Bradley Cooper gained about thirty pounds of muscle to be believably intimidating.
- Fake American:
- Playing Against Type: Bradley Cooper had been typecast as Nice Guys after Alias, so getting cast as the Bastard Boyfriend was different for him. He jokes he only got the role because the director had never seen Alias.
- Real-Life Relative: Owen Wilson's uncle is the man who laughs at the "Jabroni" joke in the Italian wedding.
- Star-Making Role: Along with Mean Girls and Red Eye, this brought Rachel McAdams to prominence.
- Throw It In!: Owen Wilson and Vince Vaughn improvised the "lock it up" banter.
- Uncredited Role: Will Ferrell as Chazz.
- Wag the Director: According to an interview Isla Fisher gave to Entertainment Weekly, the film's producers wanted Gloria to be naked for five scenes. She apparently managed to talk them down to just one. And even then, they used a body double so Isla wouldn't have to be naked on set.
- Word of God: A long standing rumor was Richard Riehle appearing as an extra in the funeral scene. He denied these in 2017.
- What Could Have Been:
Trivia / Wedding Crashers