Research on international teaching assistants (ITAs) often highlights that ITAs have at least two identities, an identity of a teacher and a student (e.g., Jenkins, 2000). Since American classrooms foster a variety of behaviors that are negotiated by instructors and students, ITAs may identify themselves with students during behavior negotiation when building rapport, especially by exchanging jokes (Unger-Gallagher, 1991). Making their student identity relevant may distort the teacher-student relationship, which ITAs might need to renegotiate. Little research has been done to show whether ITA student identity actually emerges and if does, then how. This study addresses the questions of what attributes of ITA's identities emerge during humorous exchanges with their students, how these attributes shape the teacher-student relationship, and what role humor plays in the identity negotiation process between the ITAs and their students in the university classroom. Four ITAs, all non-native English speakers, participated in this microethnographic study. This study informs research on social identity in that, most of the time, participants made the attributes of their teacher identity relevant, with teacher authority emerging as the most important attribute. While enacting their teacher identity through humorous exchanges, ITAs built rapport and created affiliation with their students. Although humor led to establishing good relationships, it did not lead to the emergence of ITA student identity. This study also contributes to research on humor in that it makes a distinction between the concepts of the target and the butt which allows for deeper understanding of how humor is used to negotiate identity. It also introduces the target switch, or a particular type of counter teasing, in which the initial target redirects humorous aggression to the teaser, thus making her/him the target and a potential butt of the tease. An optimistic finding for ITA research and research on the use of humor by non-native speakers is that even without extensive experience with American culture in general, ITAs can use humor rooted in the local context to negotiate different classroom behaviors and their identities with their students.