Rudolfa Claus is the daughter and eldest child of Santa and Mrs. Claus, the older sister of Kristin and the main antagonist of the 2000 film Once Upon A Christmas and it's 2001 sequel Twice Upon A Christmas.

In the first film, she tried to turn Christmas into a joking holiday. She later used magic to make a fake detour sign to send Kristin along with Bill Morgan and his children Kyle and Brittany in the middle of nowhere and also sent an elf dressed as a deer into the middle of the road to make them swerve into a ditch, but luckily the quartet survive. Rudolfa is later punished for her actions.

In the second film, Rudolfa (after being let off by Santa) starts to secretly sell off pieces of The North Pole to get rid of it and make Santa feel he is being replaced. Her plan is foiled by Kristin, Kyle and Brittany and Rudolfa is forced to pull Santa's sleigh in place of the reindeer.

She is played by Mary Donnell Haskell.