The present article focuses on connections between part-time special education and the good results of Finnish students in PISA studies. After a brief summary of the comprehensive school system and special education in Finland, PISA results are analysed. The analysis shows that the relative amount of special education targeted at language problems is highest in Finland among those countries from which comparative statistics are available. The writers argue that this preventive language-oriented part-time special education is an important factor behind the good PISA results.