The master’s thesis titled Fostering Relationships among Pupils with Social Games is constructed from a theoretical and a practical part. In the theoretical part, I presented socialization, its influence on interpersonal relations, and the role of a teacher in the process. In more detail, I described the use of the sociometric test. I presented the significance of social games and their influence on students. I also addressed the topic of emotions because the latter also has an important role in interpersonal relations. I performed the research in a group of extended-stay into which two classes of the second grade are included. Performing the research lasted for four months. In the empirical part, by the analysis of the data which I gained before the performance and after the performance of social games, I came to some conclusions which I presented by means of the contents analysis, graphical presentations, and the description of the selected cases. By means of a sociometric test, I ascertained that the students in the extended-stay where two classes are united prefer to socialize within their classes before the performance of social games and also after them. After the performance of social games, however, they socialize with the members of the other class more in comparison with the situation before. By the analysis of the survey questionnaire in which the students expressed their opinions about the members of the group, I ascertained that after the performance of social games, they expressed opinions about the members of the group more often. Before and after the performance, the students expressed more opinions on the members of their class than about the members of the neighboring class.