The hero and protagonist, Harry is a twelve-year-old boy with messy hair and glasses who became famous within the wizard community by surviving the curse of a powerful wizard. Harry frequently finds himself entangled in dangerous adventures but he always lives to tell the tale. Harry's character represents good intentions, innocence, and the fantasies of childhood.
Ron is tall, red-haired, and from a respected but poor family. Ron is one of Harry's two best friends at Hogwarts. He is loyal to Harry, and belligerent to their enemy, Malfoy. Ron uses experience and a process of trial-and-error to solve most mysteries. Ron's character is often overshadowed by Harry's, but Ron always manages to succeed.
Hermione is always the top student in her class. She is clever and well-read. Most spells come easily to her and remain in her encyclopedic mind. Her insight leads her to discover that the monster within the Chamber is a basilisk and that Polyjuice potion will allow the group of friends to spy on Malfoy. Principled and fond of rules, Hermione unwillingly follows the boys on their illicit adventures in order to unravel the mystery of the Chamber of Secrets.
Once a student named Tom Riddle who attended Hogwarts fifty years before Harry, Voldemort became the most powerful dark wizard ever. When Harry was a baby, Voldemort killed Harry's parents and tried to kill Harry, only to have his curse backfire and render him powerless. He is an embodiment of pure evil.
Tom's past and appearance resemble Harry's. Tom, who grew up to become Voldemort, is the last remaining descendent of Salazar Slytherin. Through his old diary he enchants Ginny Weasley to perform his dark tasks.
The gamekeeper at Hogwarts and a good friend of Harry's. Hagrid is a giant, hairy man with a strong accent and a great liking for strange and dangerous creatures. Tom Riddle frames him as responsible for the monster within the Chamber of Secrets.
The headmaster of Hogwarts. Dumbledore is a wise, powerful, elderly man with a long silver beard. He is one of the most impressive characters Harry has ever met. He has a calm, secretive demeanor and is extremely intuitive and trustworthy. He also is an egalitarian wizard, believing that all wizards, whatever their blood, have the same potential for greatness. This notion infuriates Lucius Malfoy, who tries to get Dumbledore fired from the position of headmaster.
Slimy, smirking, and snobby, Draco is Harry's greatest Hogwarts nemesis. Because his family is very wealthy, he is able to buy himself a position on the Slytherin House Quidditch team, but even though he has the fastest broomstick, he cannot play the game well.
Draco Malfoy's father, a mean, hissing man who mistreats Dobby, his house-elf, and encourages meanness and bigotry in his son. He is the head of the school governing board, and he uses his power to (temporarily) remove Dumbledore from power. Lucius is responsible for having slipped Riddle's diary into Ginny Weasley's books at the beginning of the story.
Ron's younger sister. Ginny is a shy red-haired girl with an enormous crush on Harry. She finds Tom Riddle's diary. The magic diary manipulates her into opening the Chamber of Secrets and releasing the basilisk.
Ron's brother. Percy is a prefect who is in charge of a group of younger students. He is annoying, nagging, and pompous, but has good intentions.
One of Ron's older brothers, Fred is a beater for the Gryffindor House Quidditch team. Fred and his twin brother George are troublemakers. Fred has a louder sense of humor than George, but they are almost identical and usually inseparable.
One of Ron's older brothers, George is a beater for the Gryffindor House Quidditch team. He and his twin brother Fred are troublemakers. George is subtler and more tongue-in-cheek than his twin. Together, the Weasley twins are an infamous, amusing, and charming pair.
Ron's mother. Molly is very maternal and protective, but also quite strict.
Ron's father, who works in the Misuse of Muggles Artifacts Office within the Ministry of Magic. He Muggle artifacts, and has a buoyant, childlike enthusiasm.
Harry's stuffy, nasty-tempered Muggle uncle.
Harry's unpleasant Muggle aunt.
Harry's spoiled, overweight Muggle cousin.
The head of Gryffindor House, a stern but deeply concerned witch, and a great aficionado of Quidditch.
The Potions teacher, and a slimy, ill-tempered man, Snape is the head of Slytherin House and gets great pleasure out of trying to get Harry into trouble.
The teacher of the class called "Defense Against the Dark Arts." Lockhart is the author of many magical books, and the five-time winner of Witch Weekly's Most Charming Smile Award. An incompetent, astonishingly vain man, Lockhart offers much of the comic relief in this story.
The Herbology teacher who is in the process of growing Mandrakes to save the petrified victims.
The Hogwarts caretaker, who is grouchy and adores nothing but his cat.
Filch's beloved cat, petrified by the basilisk.
The Minister of Magic, who visits to apologetically remove Hagrid.
The Gryffindor Quidditch captain and keeper.
A first year boy who follows Harry around, taking his photographs and embarrassing him tremendously; The first person to be petrified.
One of Draco Malfoy's unintelligent, lumbering cronies; Harry uses Polyjuice potion to transform himself into Goyle.
The other of Draco Malfoy's unintelligent, lumbering cronies; Ron uses Polyjuice potion to transform into him.
A belligerent Slytherin girl who has to duel with Hermione during the dueling club meeting. Hermione tries to transform into her, but becomes her cat instead.
A Muggle-born boy in Hufflepuff House who is petrified.
Percy's girlfriend, a Ravenclaw prefect who is petrified.
The Malfoy house-elf. Dobby tries to get Harry out of Hogwarts to keep him away from the danger that lurks there. he almost kills Harry by trying to save his life so many times.
Justin's friend, who suspects Harry to be responsible for the suspicious occurrences at Hogwarts.
The friendly Gryffindor ghost whose Deathday party Ron, Harry, and Hermione attend.
A ghost who haunts the girls' toilet. Myrtle was killed by the Chamber of Secrets basilisk fifty years earlier.
A poltergeist that causes harmless trouble at Hogwarts.
Harry's pet owl.
A giant spider raised in captivity by Hagrid.
Hagrid's large but friendly dog.