Students’ achievement is linked to many different factors. However, in large-scale studies, strong causal effects of factors on the achievement are hardly found, especially regarding learning environments. One can imagine that some factors can be influential for only smaller groups of teachers or for specific teaching approaches, not known in advance. If we can identify groups of teachers with specific sets of characteristics or modes of instruction, and such aspects were found to be related to student achievement, we would be able to provide school systems with suggestions about paying attention to such factors. Using TIMSS 2007 data from 16 European countries, we intend to determine groups of teachers (clusters) who use similar approaches to teaching mathematics. For clustering the teachers together with their students, we use the adapted method for hierarchical data networks of symbolic descriptions of teachers and their students. Teacher and student variables are used simultaneously. We explore characteristics which define teaching approaches in each cluster and study links between them and the mathematics achievement of students belonging to teachers in the respective cluster. Based on the comparison of student achievement between clusters, more or less successful teaching methods will be discussed.