The aim of this study is to investigate Swedish students' use of code-switching between the Swedish and English language, in relation to their involvement or interest in extramural activities. Their own views and attitudes on the topic as well as their reasons for code-switching will also be investigated in the study. The study is based on a qualitative method of research, in which semi-structured interviews were used. The participants in this study consisted of 17 students (in four focus groups) from three different secondary schools in southern Sweden. Fundamental factors connected to the study are code-switching, extramural activities,  borrowing as well as loanwords and the theory on which the study is based is called  accommodation theory. The results of the study show that the majority of total occurrences of students' use of code-switching, belonged to the word class of nouns. Other findings indicate that students use code-switching for social reasons, efficient communication and external factors, in which the situational context as well as the social context have a significant role. Many of the code-switched occurrences could also be attached to a specific extramural activity or interest. The study show that when discussing extramural activities, students frequently code-switch both consciously and unconsci ously as well as adapt their use of language, in order to make themselves understood.