This paper explores initiators of humor and the differing characteristics of humor these initiators use in elementary-level English classrooms in Korea. Forty-nine videotaped ordinary classes and interviews with four teachers were investigated. Teachers tended to make learners the subjects of humor, with this type of humor attracting students to participate in learning. Furthermore, teachers encouraged learners to pay more attention to the form of English language features by humorously revealing mispronunciations or expressions that learners could easily make mistakes with. Additionally, among learners, the primary users of humor were middle- to lower-level students. Teachers needed to build a safe environment for English underachievers who unintentionally made humorous mistakes so that they would not be mocked. Also, certain boys intentionally tried humor to get attention. It is noteworthy that teachers and learners jointly constructed humor by supporting each other. This conjoint humor reaffirms the importance of teachers’ reactions and attitudes towards pupils. By listening attentively and accepting learners’ remarks, teachers could make humorous, meaningful interactions. The current paper projects some pedagogical implications concerning how to use or deal with humor for foreign language teachers.