In recent years, especially since 2014, we have observed an unprecedented increase in the number of migrants in Poland, which is also reflected in the school community. Every year the number of migrant students grows, and with it the challenges faced by Polish schools. One of the responses of Polish legislation to these difficulties are intercultural assistants who, working in schools, support migrant students, their parents and teachers. They are also a kind of bridge connecting the Polish and migrant communities. In this article, I refer to the concept of intercultural opening, which is about building inclusive communities and institutions (including schools) for everyone, regardless of origin, nationality or language of communication. The aim of this article is to present the concept of intercultural opening as one of the antidotes to the challenges of the increasing number of migrants and cultural diversity, and the role of intercultural assistants in the process of intercultural school opening. In the first part of the article, I present the situation of migrant children in Polish schools. I refer to the statistical data and the legal framework which determine the education system of migrant children in Poland. The second part contains the concept of an intercultural opening of the school and its characteristic features, while the third one presents the role and tasks of an intercultural assistant in the process of intercultural opening of the school. The last part of the article is a summary.