The characters in the novel are often referred to by the nicknames that Botchan, the protagonist, bestows on them.

Botchan is a teacher on Shikoku, a Japanese island. Originally from Tokyo, he moves there to teach mathematics in junior high school. Because his impetuous nature and naiveté make him ill-suited to the local politics and gossip, he leaves the post in less than a year. With his youth and inexperience, he cannot maintain discipline in the classroom. Porcupine befriends and helps him, but his conflict with Red Shirt, the headteacher, and Clown, a sycophant to Red Shirt, includes a violent altercation.

Badger is the school principal of the school. He is pompous and condescending but considers himself an idealist. An indecisive administrator, he is often manipulated by Red Shirt. His nickname echoes the animal’s traditional Japanese characterization, include ineffectual authority.

Red Shirt, the head teacher, is a duplicitous, manipulative narcissist who delights in stirring up trouble and derailing others’ plans. Competing with Koga for Miss Toyama, he schemes to get Koga transferred. His actions against Botchan include deceiving him about Porcupine’s loyalty and inciting unrest among the students.

Yoshikawa, or Clown, is the art teacher. Surviving primarily through flattering the powerful, he tries to get Botchan in league with Red Shirt. An alternate translation of the nickname is “pimp.”

Porcupine, whose real name is Hotta, is the senior mathematics teacher. A warm-hearted man with a rough exterior—like his animal namesake—he befriends Botchan but becomes suspicious of his loyalties. Realizing he has been misled, he becomes the younger man’s ally and supports him before the administration.

The English teacher Koga, or Squash, is engaged to Miss Toyama, but is transferred to a distant school because Red Shirt wants to break them up and seduce the young woman.

Kiyo is a servant who works for Botchan’s family back home. A surrogate mother, she supports him with advice and gifts of money.