Princess Castle is a subtheme of DUPLO Castle. Primarily aimed towards young girls, the sets all involve the Princess and her companions. Three sets were released in 2005, and three more in 2007.
The colours of the sets are mostly white, and many different shades of pink, the sets either focused on castle or ponies and/or horses. All the sets but 4825 Princess and Horse came with a pink tower or castle roof piece.
The DUPLO Figures were either princesses or princes; all the princesses had long hair with a golden crown and a dress of either gold, pink or blue.
- The theme does not have a unique logo, although the boxes of all the sets feature a butterfly prominently.