Die Hard is considered a Christmas movie because it takes place during the holiday season and has a lot of Christmas elements in it. It takes place during a Christmas party, and the main character, John McClane, wears a red Christmas sweater throughout the movie. There are also many references to Christmas, such as the Christmas music playing in the background, the decorations in the building, and the fact that McClane is trying to save his wife, who is trapped in the building during a Christmas party.