This research was conducted to explore and compare the attitudes of Greek educators towards immigrant children and children with special educational needs, as well as to establish some social-demographic differences in Greek teachers’ attitudes. The research tool used in this research was the questionnaire. The scale of answering was a five-degree Likert scale, and only one question was yes/no. The statistical program used for statistical analysis of the data was the IBM SPSS program. Descriptive statistics, correlation coefficients, and chi-square analysis were used. The sampling method used in the present research was the feasibility sampling, and even the homogeneity technique was used. In this research, all the participants were educators. The research sample consisted of 150 participants. Modern Greek schools contain to a large extent migrant students and students with special educational needs. Based on this research, there were found several similarities in Greek teachers’ attitudes towards immigrant students and students with special educational needs, but there were also some differences. The most negative attitudes towards immigrant students were expressed overtly by the male Greek teachers, at 18-29 years old, married, with one child, teaching history in secondary education, with the period of educational experience of 11-20 years, and the most negative attitudes towards the students with special educational needs were expressed overtly by the female Greek teachers, with PhD, in bad or very good economic situation, divorced, teaching in primary school for more than 10 years at school. The Greek school, although it is a "mosaic of students" with different educational, cognitive, political, social, economic, historical, linguistic and cultural specifics, insists on its monocultural orientation, the rejection of diversity, isolation, and stereotypes. Given these results, it is necessary in the future to explore the effective ways to reduce these perceptions, if not destroy them.