Teasing is often associated with childhood, but it has been found to be ubiquitous, arising across a wide range of different interactional settings in different languages and cultures. It is of particular interest to those undertaking research about humor, because teasing is multilayered, invariably mixing elements of provocation and non-seriousness. The mixed set of messages accomplished through teasing is what lends itself to being interpreted and evaluated in different ways by participants. However, teasing not only combines provocation with various modes of non-seriousness, including but not limited to being framed as humorous, but itself involves a range of different practices. In other words, teasing constitutes a heterogeneous category of behavior. The multilayered and heterogeneous nature of teasing has made its relationship with humor a complex one. While it may be claimed that the teasing is playful or done in jest, it can easily slide into being characterized as aggressive, and so may also be construed by participants as a covert form of bullying or harassment. The diverse range of practices by which teasing is accomplished in interaction, and the different interpretations and evaluations that may be occasioned among participants in the course of episodes of teasing in interaction, have thus made it fertile ground for study across a wide range of disciplines.