A general assumption of school-effectivenss-research is that pupils´ performance (considering knowledge, social and motivational aspects) can be improved through reorganization of the schools' environment. According to findings of school-effectivenss-studies (Scheerens & Bosker, 1997) one of the general effectiveness-enhancing factors is social climate in schools. Two lines of research have dealt with social climate in schools, the first one focussing on social climate on classroom-level (e.g. Moos, 1979), the second one dealing with the organizational climate on school-level (e.g. Halpin & Croft, 1963). Few have tried to combine aspects of climate on classroom- and school-level (e.g. Ellett & Walberg, 1976). This paper presents an empirical attempt to combine the perceptions of social climate on classroom- and school- level. The data used is based on a German follow-up study (KESS 4) of the international study PIRLS (Progress in International Reading Literacy Study). In this study on the one hand tests to identify reading skills, mathematics and science comprehension of fourth grade students were implemented, on the other hand background questionnaires for students, parents, teachers and headmasters were used to investigate the social background, conditions of learning and attitudes towards learning and school. These background questionnaires are used to draw conlcusions about the perception of the social climate from different perspectives.