In the English language, humour is defined as the ability to find things funny, the way in which people see that some things are funny or the quality of being funny, but the notion of humour encompasses much more than that. This thesis combines theoretical knowledge of humour, the application of humour in the language classroom and its effects on the students who learn with the help of humour or learn about humour. From a brief history of how the theories of humour evolved, we are able to see a positive shift in the philosophical approaches towards humour. From being thought of as irrational and aggressive, during the eighteenth century, humour and laughter began to be regarded as a rational way of enjoying incongruity. From an evolutionary point of view, comparing humour to a kind of play describes it as a way for our cognitive functions to deviate from practical thinking, while remaining rational. Since theories prove how relevant humour is, we can presume that it would have positive effects in the school environment, and also in the language classroom, which is the focus of our interest. Humour can be introduced in the classroom in two ways: as an aid of achieving certain learning and management objectives, and as the subject of teaching. The effects of using humour in the classroom are various (intellectual, physiological, psychological, educational) and beneficial. The effects of humour in the classroom were examined and confirmed in a study which was carried out in the Ksaver Šandor Gjalski primary school in Zabok on the sample of more than a hundred participants. The results of the study show us that the students have a positive attitude towards the use of humour in the classroom and that humour has a positive effect on their mood, attitude and learning in general.