In the last few years 200,000 people immigrated to Sweden, which means that new and higher demands are made on those who work in the school system when Swedish school has developed and become more multicultural and multilingual. The National Agency for Education (2016) mentions that there is a large proportion of multilingual students who do not achieve the goals in mathematics in compulsory school. This knowledge review will highlight and investigate the importance of the Swedish language for multilingual pupils' learning in mathematics and furthermore at the end it is also explained how teachers can work to see multilingualism as a resource in mathematics teaching. The method for collecting data relevant to our study involved; various databases, manual searches, secondary sources and consultation with our supervisor and other course mates. The basis of our study is based on scientific articles, course literature, books and dissertations that were considered relevant to our research area. The results presented in this paper are arranged to provide concise knowledge of the Swedish language's importance for multilingual pupils' learning in mathematics. An explicit focus on the understanding for seeing multilingualism as a resource in mathematics classroom in compulsory school.