To protect Mackenzie Foy on the set, Bill Condon had set up a swear jar where any cast and crew members caught swearing or uttering profanities were fined on the spot. The amount collected from the jar was donated to St. Jude's Children Hospital.
Besides Mackenzie Foy, 10 actresses portrayed the rapidly-growing Renesmee Cullen, as well as a CGI-animated baby.
Every song that appears in the film and on the soundtrack is original and written specifically for the film.
Both an animatronic baby and three-week-old babies were used in the film. Kristen Stewart preferred working with the real babies because she felt they helped her give a better performance.
(at around 1h 11 mins) The inscription inside the locket Bella gives to Renesmee, "Plus que ma propre vie", is French for "More than my own life".