Common international student assessments have become a global phenomenon in recent years. Accordingly, there has been significant emphasis on students’ performances on international assessments in Turkey. This study investigates the changes in Turkish students’ achievement in PISA assessments between 2003 and 2009, with specific attention paid to the achievement gaps between students who reside in different regions and who attend different types of schools in order to explore the areas that policy makers need to focus on. The results indicate that the situation in terms of the achievement gaps between different types of schools does not seem very promising, although there are some positive signs regarding closing the achievement gaps between different regions. In this context, there is a need for special attention toward improving the quality of education at the lowest performing high schools, such as general high schools and vocational high schools, in order to increase Turkish students’ average achievement.