For reasons unclear, Sara Paxton replaced Kimberly J. Brown as Marnie in this film despite Brown being fully available for the shoot. Brown has publicly stated her disappointment with the recasting.
Debbie Reynolds, Judith Hoag, and Joey Zimmerman are the only actors to appear in all four Halloweentown films.
Millicent Martin was originally cast to replace Debbie Reynolds as Agatha Cromwell due to scheduling conflicts. When Reynolds' schedule cleared up and she could return, Martin's role was reworked into a new character.
This is the only Halloweentown film not to feature Sophie Piper (Emily Roeske), since Roeske retired from acting after Halloweentown High (2004).
Sara Paxton dyed her hair brown for this movie. Kimberly J. Brown, who played Marnie in the first three films, has naturally brown hair.