During the last few years, across Europe, special education has been orientated towards an inclusive model. Accordingly, in Greece, special education functions as an integral part of general education. However, few studies have investigated how children in the mainstream school understand diversity issues and specifically learning difficulties. The present study investigated typically developing children's understanding of and attitudes towards diversity, and peers with learning difficulties. For this purpose, children aged 9-12 years, completed a questionnaire with mainly open-ended questions and some close-type questions. Regarding children's understanding of diversity, the majority of responses focused more on individual/personality differences, on biological differences and less on disabilities or difficulties. Research into children's understanding about the causes of learning difficulties demonstrated misunderstanding, while a large number of children had a total lack of knowledge. On the other hand, they seem to understand that learning difficulties may affect all the aspects of life. Children's attitudes towards school inclusion were positive on a more superficial level. Results are discussed in terms of educational implications and school practice for the development and implementation of appropriate intervention programs. (Contains 5 tables and 1 note.)