Wilbur is a spring piglet born as a runt. Because of his small size, he requires bottle-feeding and extra warmth during his first weeks of life. He possesses an anxious but deeply affectionate personality and frequently ponders the nature of his existence. Moving to the Zuckerman farm introduces him to a larger world where he seeks companionship and relishes his meals of warm slops.

Charlotte A. Cavatica is a large grey barn spider who lives in the upper doorway of the Zuckerman barn. She catches flies and other insects to survive, a practice she defends as necessary for controlling the bug population. Despite her predatory nature, she maintains a calm, maternal demeanor and speaks with precise, educated vocabulary. She observes the human and animal routines with sharp intelligence.

Fern is an eight-year-old girl with a strong sense of justice and a deep attachment to animals. She successfully pleads for Wilbur's life and dedicates her spring to bottle-feeding him and pushing him in her doll carriage. After Wilbur moves to her uncle's farm, she spends her summer afternoons sitting quietly on a stool in the barn, listening to the animals talk.

Templeton is a large rat who resides under Wilbur's feed trough at the Zuckerman farm. He operates strictly on self-interest, dedicating his time to eating, collecting odd items, sleeping, and hiding out of sight. He actively dislikes sentimentality and prefers to observe the farm's daily events from a cynical distance.

Homer Zuckerman is Fern's uncle and the owner of a well-kept farm down the road from the Arable property. He is a confident, traditional farmer who provides his animals with comfortable habitats and regular meals. He values routine and relies heavily on his hired hand to keep the property running smoothly.

The Goose is a vocal resident of the Zuckerman barn who spends the spring carefully incubating her clutch of eggs. She is highly talkative, habitually repeating her words in a rapid-fire stutter. She enjoys stirring up mild trouble, such as pointing out a loose board in Wilbur's pen to encourage an escape.

Doctor Dorian is the local county physician. He wears thick glasses and maintains a long, bushy beard. Unlike many adults in the community, he possesses a calm, open-minded disposition and willingly considers the possibility that animals might communicate, preferring to marvel at nature rather than dismiss it.

The old Sheep has lived on the Zuckerman farm for many seasons. She holds a cynical view of the humans' intentions and does not hesitate to share grim farm realities. She finds Wilbur's emotional outbursts irritating and prefers the quiet predictability of her own routine.

Lurvy is the hired hand at the Zuckerman farm. He wears patched clothes and handles the daily physical labor, from pouring feed to fixing fences. He is obedient to Mr. Zuckerman's orders and maintains the routine that keeps the animals content.

Mrs. Arable is Fern and Avery's mother. She manages the household and keeps a close eye on her children's behavior. She is prone to worry, particularly regarding Fern's insistence that the Zuckerman barn animals speak to one another, prompting her to seek medical advice about her daughter's mental state.

John Arable is a practical farmer who makes unsentimental decisions about his livestock. He wears a farmer's hat and has a tall, lanky frame. Despite his pragmatic approach to agriculture, he demonstrates a soft heart when his daughter challenges his decision, choosing to use the moment as a teaching opportunity rather than forcing his authority.

Avery is Fern's older brother. He is a highly active boy who charges into situations without thinking, often carrying weapons or wild animals he has captured. He breaks things, falls into traps, and constantly views the farm as his personal playground for loud adventures.