This paper offers an explanation for the phenomenon of laughter in the ESL classroom. An analysis of the discourse that took place in an advanced-level intensive ESL classroom revealed that 3 Korean women in the class laughed when their participant role, or footing, in the classroom interaction changed from principal to author (Goffman, 1981; Kramsch, 1993). In other words, the students laughed when the content of their speech shifted from strict adherence to perceived student role norms to expression of personal sentiments. The Incongruity Theory of Laughter (Morreall, 1983) supports the claim that students' laughter may indicate that such a change in footing represents a deviation from the cultural model they hold for classroom interaction (Gee, 1999). Because authorship in the classroom has been shown to enhance the development of students' oral academic language proficiency (McCreedy, 1998). ESL teachers should explicitly sanction student authorship in their classrooms and create opportunities that invite it.