The fictional town of Treegap, the wood, and the home of the Tucks in the year 1880 and in the year 1950.
Winnie Foster - Winnie is a ten-year-old girl who as an only child is overly protected and stifled with rules. She desperately wants to run away from this and her decision to leave her yard and go into the Wood sets into motion the plot of the story.
Mae Tuck - The mother of the Tuck family, Mae is very kind and compassionate. She is also quite untidy in her housekeeping, but a loving wife and mother nonetheless.
Angus Tuck - He is the father of the Tuck family and though outwardly gruff, he makes Winnie somehow love him the most of the entire family. He is very wise about drinking from the spring or telling anyone their secret.
Miles Tuck - He is the oldest Tuck child and appears to be about twenty-one or twenty-two years old. When he and Jesse leave home to seek a life away from their parents, he seems more responsible, holding such jobs as carpentry and blacksmithing.
Jesse Tuck - He is the youngest son of the Tuck family and stopped aging at 17. He is a free spirit who does what strikes him at the moment. He is quite handsome and he and Winnie fall in love.
The Man in the Yellow Suit - He is the villain of the story, a strange man who wears unusual clothing and is looking to find the spring, which will give him eternal life and make him a lot of money.
The Toad - This creature is Winnie’s first real friend, but it takes her awhile to realize it. It seems to follow her everywhere she goes, and she develops a keen sense of caring for it. It is also a symbol of metamorphosis and change.
Winnnie’s Parents and Grandmother - They are overly protective of Winnie and stifle her desire to grow and change. However, they recognize the change that takes place in her after her experiences with the Tucks and support and love her even more. They also give her the space to grow that she needs.
The Constable - He is the character who arrests Mae for the murder of the Man in the Yellow Suit and is forced to let Winnie out of prison, because she is so young.