In this presentation, the concept translanguaging space (Li, 2011, Zhu et al, 2017) is used to study classroom interaction in a Mother Tongue Tuition (MTT) classroom in Arabic. The case of Arabic here makes translanguaging space relevant for the study of classroom interaction in relation to the diglossic situation between MSA and varieties of Arabic. The aim with the article is to study classroom interaction in MTT Arabic as a translanguaging space. The study is part of a larger project on Mother Tongue Tuition in Sweden which is carried out in the form of action research combined with linguistic ethnography. Material used is from one teacher and students in grade three and consists of fieldnotes, audio recordings from classroom observations in MTT Arabic and one teacher interview. The use of translanguaging space, as both an arena for translanguaging and a space created through translanguaging (Li, 2011) makes visible the seamless shuttling between varieties, which is natural and necessary in Arabic language classrooms. The diglossic situation in Arabic means that while all students need to learn MSA, the challenges are greater for students with varieties that diverge more from the teacher’s. In this case the teacher’s Levantine dialect was closer to that of some of the students, while other dialects diverged more. The critical and creative aspects inherent in translanguaging space put issues of student engagement and participation in focus. In this case, the teacher was in the center and students were rather passive, answering questions and performing given tasks. Although the dominance of MSA and Levantine may be interpreted as a monolingual classroom policy, the fact that both Swedish and other dialects were accepted shows that the diglossic situation opened up the classroom as a translanguaging space.