This thesis is written because of the researcher’s interest for the non-Formal education in Greece and, more specifically for the non-Formal schools in which adult immigrants learn the Greek language. This study deals with the teachers who work in formal education and at the same time, they teach Greek language to adult immigrants, voluntarily. The purpose is to determine, through the interviews of the teachers, if there is interaction between formal and non-Formal education and if the non-Formal education could be an alternative mode of operation for formal education in Greece.