Princess Mia Thermopolis is a fictional character from the The Princess Diaries series, created by author Meg Cabot. She is a teenager who discovers she is the heir to the throne of the small European principality of Genovia. Mia navigates the challenges of adolescence while learning about her royal responsibilities. Throughout the series, Mia faces various personal and social issues, including friendships, romance, and self-acceptance. Her journey is marked by humor and relatable experiences, making her a beloved character among young readers. The series has been adapted into popular films, further increasing her recognition.