This study aimed to analyse and explore through systematic observation the conflicts that occur among peers during the playground in elementary schools in Spain. The study followed a non-experimental descriptive design and all conflicts were observed in their natural context of 44 schools. Among the 1691 conflicts detected in a sample of 2529 students, significant differences were found among the different types of conflicts (verbal, physical, social exclusion and sexual harassment), which depended on the course and sex of the protagonists. Furthermore, a different pattern emerged in the reactions that other peers and teachers had to the initial conflicts. Additionally, findings were consistent with the findings in previous studies in the literature regarding the need to train and prepare teachers to prevent future conflicts in the scholar context.