One of the novel's two protagonists, Mary Lennox is a ten-year-old girl who, after the death of her parents in India, is sent to live with her uncle in Yorkshire, England. Mary changes drastically over the course of The Secret Garden: she evolves from a spoiled, unloved and unloving creature to a girl who is full of spirit and surrounded by friends. She begins the book as its central character, but is later displaced by Colin.
The other of the novel's protagonists, Colin Craven is Archibald Craven's ten-year-old son and heir. He was born shortly after the death of his mother, and his father could not bear to look at him because of his resemblance to her. It is feared that he will grow to be a hunchback like his father, and he has been treated as an invalid since his birth. Colin's childhood has been entirely bedridden, and his servants have been commanded to obey his every whim. As a result, Colin is extremely imperious and gloomy; when we first meet him, he is certain he is going to die. By novel's end, however, he too will have undergone a transformation: he will have become a vigorous optimist, and will have won his father's love. Both his and Mary's conversions are effected by the magical properties inherent in the secret garden.
Dickon is alternately described as "a common moor boy" and "a Yorkshire angel"; he is both. Two years older than Colin and Mary, Dickon has lived on Missel Moor his entire life, and has a uniquely intimate relationship with the land. He is described as looking like the god Pan (the god of ...): he has rosy cheeks, rough curly hair, and blue eyes precisely the same color as the sky over the moor; he even carries a set of pan-pipes. Like Pan, he has the power to charm both animals and people: all the creatures who come close to him are instantly tamed, and he counts a fox, a crow, and two wild squirrels among his pets. His power to tame creatures works on Colin and Mary as well, and is one of the central causes of their wondrous transformations. He is the brother of Martha and the son of Susan.
Mary's friend and maidservant, Martha is distinguished by her charming frankness and levelheaded approach to all aspects of life. Her simplicity and kindness are a great help to Mary upon the latter's arrival at Misselthwaite. In her very ordinariness, Martha represents the goodness of all the people of Yorkshire.
Ben Weatherstaff is a gruff elderly gardener who is only permitted to stay at Misselthwaite because he was a favorite of the late Mistress Craven. He introduces Mary to the robin redbreast, and helps the children keep the secret of the garden. Ben himself clandestinely tended the garden during the ten years in which it was locked, out of love and loyalty for the Mistress Craven. Although he is rather rough, Ben's essential kindness is fundamental to his character.
The master of Misselthwaite Manor, who suffers from a crooked spine and general ill health. He has been in a crushing depression ever since the death of his wife, ten years before the novel begins. Archibald spends most of his time abroad, since he wants to see neither his house nor his son, Colin, because these remind him of his late wife. At novel's end, he undergoes a change of heart after his wife comes to him in a dream. Master Craven comes to embrace his son when he realizes that this latter is in perfect health.
Archibald's late wife, who died ten years before the outset of the novel. Her spirit is associated with both roses and the secret garden. Her portrait hangs in her son's room beneath a rose-colored curtain, and she is described by all who knew her as the gentlest, sweetest, and most beautiful of women. She represents an absent ideal.
The mother of Martha and Dickon (as well as of twelve other children), Susan Sowerby functions as a symbol for the concept of motherhood itself. She is all-nurturing, all-knowing, and appears dressed in a hooded blue cloak like that of the Christian Virgin Mary (the mother of Jesus Christ). Both Mary and Colin express the wish that she were their mother; stories of her sustain each of them before their respective transformations.
The head of the servants at Misselthwaite Manor, Mrs. Medlock is distinguished by her punctilious obedience of all of Master Craven's odd rules. Beneath her rigid exterior, she, like all the people of Yorkshire, is basically kind. She and Susan Sowerby were friends in their girlhood.
Archibald's brother and Colin's uncle, he tends to Colin during the latter's illness. He is a bit stuffy and officious, and both Colin and Mary laugh at him at every opportunity. Described as a weak man, he half-hopes for Colin's death so that he might inherit Misselthwaite.