The former couple reportedly decided not to attend the event so as to not run into each other and face a possibly awkward reunion.
The movie won awards for best romance and best sci-fi/fantasy film. Stewart won two awards for her performance while Taylor Lautner and Pattinson won one award each.
"Robsten" ended their thee-year relationship for the second time May 19, about a year after Stewart was photographed cheating on Pattinson with "Snow White and the Huntsman" director Rupert Sanders.
The two began dating while filming the first installment of the Twilight saga.