<p style="text-align:justify">Aggression in early childhood is considered to a common problem. Identification, reduction and prevention of aggression, especially in early childhood are also considered prevalent. Preschool teachers are known as one of the most important people in children’s lives as they are the first ones to meet the child after parents. Therefore, they hold an important role in identifying, reducing and preventing child aggression observed in early childhood. The purpose of the present study is to examine the knowledge and the awareness levels of preschool teachers about aggression and aggressive behaviours. The study is based on phenomenological approach, as one of the qualitative research designs. A semi-structured interview form, prepared for the study based on expert opinions, was applied to the participants. On the light of the findings from the preliminary findings, the related form was applied to a second group of teachers over the internet. Besides, an additional scale consisting of the items of two different instruments directed to determine the aggressive behaviours of preschool children were formed and applied to the second group of participants. The last scale, which was prepared depending on the findings obtained from the second group of teachers, was applied to a third group of participants because the first two participant groups could not recognize and define relational aggression. The relevant themes and sub-themes were created from the data obtained and the findings were discussed within the scope of the literature. According to the results of the study, it was seen that preschool teachers generally defined aggression as physical and verbal harm, and similarly, aggressive behaviours were categorized under physical aggression and verbal aggression types. It was determined that teachers generally recognized relational aggression when they saw the items related to it in the scale. However, they hardly emphasized it while they were defining aggression. So, it can be said that preschool teachers have limited knowledge and awareness of relational aggression as they recognize it only when they see it but can neither define nor name it. The results are discussed and some suggestions are recommended.</p>