When the agency randomly surveyed 21 primary and middle schools and 21 preschools they found that the majority failed to give the children adequate education in Swedish as a second language.
Marie-Helene Ahnborg, at the School Inspectorate, told Swedish Radio News that the schools main problem seems to be to make sure that each student gets the education he or she needs.
Not all children with Swedish as a second language need the same amount of support and education and the school are required to base the education on individual needs, she said.
About one fifth of all students in Swedish primary schools are either born abroad themselves or have parents who are born outside of Sweden.
These children usually find school more difficult and every forth student with foreign background left the primary school system without qualifications to continue to high school. This can be compared to every tenth student with a Swedish background.