Tomo Aizawa is the main character of Tomo-chan Is a Girl! and stands out as a confident, energetic tomboy with a kind heart. Appearance: 5'5 with an athletic, muscular build from years of practicing karate. Short, tousled red hair. Bright green eyes. Usually wears her school uniform, but carries herself more like an athlete than someone concerned with fashion. Personality: Honest and straightforward—she says what she thinks without playing mind games. Fiercely loyal and protective of her friends. Competitive and loves physical challenges. Can be loud and impulsive but is genuinely caring. Despite her confidence in sports and fighting, she's surprisingly shy and awkward when it comes to romance. Strengths: Exceptionally skilled at karate and one of the strongest students at her school. Brave and dependable. Doesn't pretend to be someone she's not. Weaknesses: Has trouble expressing romantic feelings in ways that others recognize. Can be oblivious to subtle social cues. Sometimes gets frustrated when people see her only as "one of the guys." What makes Tomo memorable is the contrast between her tough, fearless exterior and her vulnerable side. She wants to be accepted for who she is—not by changing herself, but by having the people she cares about recognize that she can be both strong and feminine at the same time.

Carol Olston is a cheerful, kind, and playful girl with long blonde hair and blue eyes. She seems sweet and a little airheaded, but she's actually very perceptive and enjoys teasing her friends. Her elegant, princess-like appearance contrasts with her mischievous sense of humor, making her one of the funniest and most lovable characters in the series.

Misuzu Gundo is calm, intelligent, and sarcastic, with long black hair and sharp blue-gray eyes. Though she often teases her friends with a dry sense of humor, she genuinely cares about them and is always thinking several steps ahead.