Decades of research have associated effective emotion and behaviour regulation with learning and social competence among young children. However, further studies on children's use of emotion regulation in their everyday lives are required. This study focuses on investigating six- to nine-year-old children's (N?=?24) use of emotion regulation strategies in various socio-emotionally challenging classroom situations. Data consist of video recordings of different classroom situations, which were analysed using interaction analysis and theory-oriented content analysis in connection with the Multisource Assessment of Social Competence Scale questionnaire results on social competence. The results of this study indicate the differences in children's abilities to use emotion regulation strategies appropriately in socio-emotionally challenging classroom situations. Qualitative features of children's strategies in different situations also vary. These findings, along with those of previous studies, suggest a need for teachers to scaffold children's developing skills of emotion regulation in school contexts.