ELF interactions are characterized by the use of English as a language of communication among speakers who do not share the same mother tongue. However, its function goes beyond that. Participants in casual conversations complain, gossip, curse, joke, laugh, cry etc. together and, by doing that, they establish rapport with one another. ELF interactants do the same with only difference (but not a hindrance) that they do so in a language other than their mother tongue. Humour is a characteristic shared by all human beings, even though the way and the extent to which they practise and enjoy it, varies from one individual to another. The research on humour in ELF interactions was conducted under the assumption that one's sense of humour does not necessarily depend on one's mother tongue, i.e. non- native speakers can be 'funny' in English just as they can be in their respective mother tongues. The book is not only directed towards those interested in English studies, in particular ELF studies, but also disciplines such as cultural studies, anthropology and linguistics.