Marinette is a kind, creative, and energetic teenage girl who can sometimes be nervous or clumsy, especially around Adrien. She cares deeply about her friends and is always willing to help people. As Ladybug, she becomes more confident and focused, taking on the role of a natural leader. She has blue-black hair in pigtails, blue eyes, and usually wears a pink or white top with jeans. As Ladybug, she wears a red-and-black spotted suit and uses her yo-yo as her main weapon.

Adrien is a polite, friendly, and somewhat sheltered teenage boy. Despite growing up wealthy, he genuinely cares about other people and wants to make friends and experience a normal teenage life. As Cat Noir, he becomes much more playful, confident, and joking. He has blond hair and green eyes and normally wears fashionable clothes. As Cat Noir, he wears a black cat-themed suit, with a bell around his neck and a staff that he uses in combat.

Chloé is wealthy, confident, and very outspoken. She can be bossy and mean toward other students, particularly Marinette, and often acts as though she's better than everyone else. However, she occasionally shows that she does care about people close to her. She has long blonde hair and blue eyes and usually wears fashionable designer clothes.

Alya is Marinette's best friend and one of the most energetic people in the class. She's curious, determined, brave, and obsessed with discovering the truth behind Ladybug and Cat Noir. She runs the Ladyblog, where she posts about superheroes and their battles. She has brown skin, reddish-brown hair, and glasses, and usually wears casual clothes with a red-and-white color scheme.

Nino is Adrien's best friend and is relaxed, friendly, and easygoing. He's usually the person who helps Adrien have fun and experience a more normal teenage life. He's also a DJ and loves music. He has brown skin, dark hair, and wears a backwards cap, headphones, and casual streetwear.

Sabrina is Chloé's best friend and often follows her around. She's intelligent and organized but can be very eager to please Chloé, sometimes allowing herself to be pushed around. She has short reddish-brown hair, glasses, and usually wears a school uniform.

Ms. Bustier is Marinette and Adrien's homeroom teacher. She's patient, kind, and encouraging toward her students. She tries to teach them to work together and treat each other with respect.

Gabriel is Adrien's strict and highly successful father and a famous fashion designer. He is serious, private, and extremely protective of Adrien. Behind the scenes, he becomes Hawk Moth, using the power of the Butterfly Miraculous to turn negative emotions into supervillains. As Hawk Moth, he wears a white suit with purple and black details, along with a butterfly-themed mask.