This paper presents the results of a European study investigating the extent to which the Dynamic Approach to School Improvement (DASI) can help schools situated in socially disadvantaged areas to improve their effectiveness. At the beginning of the school year 2015–2016, a sample of 72 primary schools in four European countries (Cyprus, England, Greece and Ireland) was randomly allocated into the experimental and control groups. A questionnaire measuring the functioning of school factors related with the school learning environment, school policy for teaching and school evaluation was administered to all teachers of the school sample (n = 762). A battery of mathematics tests and a questionnaire measuring students’ socioeconomic status (SES...