Geronimo Stilton is about the titular character, a mouse journalist and head of the Geronimo Stilton Media Group. He searches New Mouse City and places around the world for new scoops while having adventures along the way with his nephew Benjamin, cousin Trap, sister Thea and Benjamin's friend Pandora Woz. Most episodes share no story connections and are generally self-contained, though some episodes feature ties and characters from others.

Patrizio Prataas Geronimo Stilton (voice)
Monica Bonettoas Benjamin Stilton (voice)
Debora Magnaghias Thea Stilton (voice)
Riccardo Peronias Trap Stilton (voice)
Marco Balbias Torquato Travolgiratti (voice)
Tosawi Piovanias Pandora Woz (voice)
Emanuela Pacottoas Pandora Woz (voice)
Patrizia Salmoiraghias Sally Rasmaussen (voice)
Riccardo Rovattias Professor Van Volt (voice)
Mario Zuccaas Gianratto Crostaccia (voice)