This study examines religious identity development of pupils at Dutch schools for secondary education (mean age 16.4). With the help of a theoretical conceptualization of "religious identity development" empirical research is carried out. Main question is whether differences in terms of religious commitment and exploration between pupils of the four participating schools can be explained by religious denominations of pupils and the importance the pupils' parents attach to worldview. It is concluded that school in general has no significant main effect on religious commitments and explorations of pupils. Religious backgrounds of pupils should be taken into account. Because pupils themselves do indicate that school has influence on the way they look at life, further research is needed in which specific school aspects (like the way pupils evaluate religious education) should also be taken into account. (Contains 8 tables.)