This thesis discusses how a person's personality traits in the Big Five affect his/her language learning abilities. It is about both language learning and psychology and delves deep into how the two are interconnected. It also contains a study, which gives evidence for the findings. The literature on which the scientific background is presented is diverse, as it contains long-standing, much-cited sources, and recent, fresh studies as well. The conclusions are clear and logical. It could also be a basis for further research.