This essay investigates the motivation of newly-arrived immigrant students, in the Swedish upper secondary school system, in connection with their simultaneous studies of the Swedish and English language. The essay investigates the students’ motivation as well as their linguistic self-confidence during their simultaneous studies. In order to investigate these factors, this essay uses the operative terms from Gardner and Lambert in their study of student motivation in regards to language learning. These terms codify and structure student motivation into two groups, integrative motivation and instrumental motivation. The former term denoted motivation based on the will to integrative and communicate with native speakers. The latter term instead denoted motivation based on the will to use the language in purely practical terms, for example for advancement in the work force or in educational institutions. This essay also uses the aforementioned term linguistic self-confidence as used by Dörnyei. The term denoted a speaker’s confidence in their own proficiency in a language. The selection process of the study showed that the improvement, of the students’ knowledge, was visible in both languages. However, there was no clear indication as to whether integrative or instrumental motivation had a greater effect on the improvement. Previous research indicates that integrative motivation had been more successful in language learning. The study showed a connection between the students’ linguistic self-confidence and their improvement. This further emphasises the importance for students to recognise their own progress and thus strengthen their linguistic self-confidence, which useful information for language teachers active in a simultaneous language learning situation.