The necessity of this study was determined by the importance of the issue of migrant children’s language adaptation. Migrant children are arriving in Russia having no knowledge of the Russian language but at the same time schools and other educational organizations are not prepared to cater to these children – there is a lack of tested methodologies that are evidence-based and effective in teaching Russian as a second language to migrant children. This study was aimed at (1) examining the process of migrant children’s language adaptation in the context of primary school education and (2) developing an effective communicative methodology for teaching Russian to migrant Muslim children and helping them adapt. The main research method used in this project was a pedagogical experiment that followed observing-reporting, formative and control stages. We also used statistical analysis and expert evaluations. 152 primary school migrant children took part in our research project. The teaching methodology was designed with respect to positive language transfer (positive cross-linguistic influence) and linguistic interference (negative cross-linguistic influence). The main distinguishing feature of the developed methodology is that it is based on the model that uses three languages in the educational process – going from the native language of children (Uzbek) to Tatar and then transitioning to Russian. Our findings confirmed the effectiveness of the developed methodology as its use helped children significantly improve their Russian with some of them achieving the level B1 in a relatively short period of time. Parents, primary school teachers and other educators might find this article interesting and useful.