Thea Stilton
Thea Stilton herself.
Vital statistics
Name Thea Stilton
Gender Female
Species Mouse
First appearance Lost Treasure of the Emerald Eye
Residence New Mouse City
Thea Stilton is Geronimo Stilton's younger sister[1]. She gives Geronimo a lot of trouble. She has a motorcycle. She is special correspondent of The Rodent's Gazette. She does not know that Hercule Poirat has a crush on her!


She is gray unlike Geronimo, she has purple eyes and always wear a coat and a pink shirt and blue pants. 


She appears in almost all the Geronimo Stilton books, sometimes briefly. She always appear in the Thea Sister books.


  • Thea's fur is gray unlike Geronimo's which his fur is brown.
  • She is a adventure mouse unlike Geronimo.
  1. Since Thea refers Geronimo as "Big Brother" sometimes,she must be his younger sister