Michael (Mike) Wilson [Male]: The main character of this novel. The original Mike was an orphan who was taken in by his father's sister family.

Helen Grace [Female]: Mike's aunt. A woman in her early thirties who recently got divorced. She is moved to her new place with her children and Mike. She is originally from New York City, New York, and is currently living at the Spiderwick Estate on Ducal Drive. (Source: The Spiderwick Chronicles)

Richard Grace [Male]: He is Simon Grace, Jared Grace, and Mallory Grace's dad. He is also the ex-husband of Helen Grace. He lives in California. HE didn't appear in the novel. (Source: The Spiderwick Chronicles)

Mallory Evan Grace [Female]: She is Jared and Simon's 13-year-old sister. She is the oldest child of the Grace family. She is a fencer. She is more mature compared to her brothers and to have grown to be more adventurous and risk-taking. (Source: The Spiderwick Chronicles)

Jared Evan Grace [Male]: He is the nine-year-old son of Helen and Richard Grace. He has a twin brother named Simon, and an older sister named Mallory. After his parents split up, he was not happy. He had already begun to get into fights and was causing trouble. (Source: The Spiderwick Chronicles)

Simon Evan Grace [Male]: He is the twin brother of Jared and he is somewhat nerdy and is respectful of authority. (Source: The Spiderwick Chronicles)

Lucinda Spiderwick [Female]: She is the Grace Children's aunt and Arthur Spiderwick's daughter. She formerly lived in the Spiderwick Estate and now lives in the psychiatric hospital. She's related to the Grace family and is a part of the Spiderwick Family. (Source: The Spiderwick Chronicles)

Arthur Spiderwick [Male]: He is great-aunt Lucinda's father. He wrote a book a Field guide about the many Faeries he has encountered. (Source: The Spiderwick Chronicles)