Bullying is an aggressive act carried out repeatedly by one person or group of people who is stronger or more powerful towards another person with all forms of oppression or violence carried out intentionally with the aim of hurting, even if it is carried out continuously. This research aims to determine teachers' communication strategies in an effort to prevent bullying as well as knowing the factors that cause bullying and the forms of bullying that occur at the Mangunan Purwomartani Kalasan Experimental Elementary School, Sleman. One of the factors causing bullying is that it is triggered by negative attitudes. Meanwhile, the form of bullying is carried out verbally, physically, socially and emotionally. So that victims of bullying feel depressed, traumatized and helpless. This certainly has a big impact, especially for students, where the student learning process experiences obstacles so that the teaching and learning process does not run optimally. For this reason, teachers need to have a communication strategy in an effort to prevent acts of bullying by providing firm and clear guidelines against bullying as well as making agreements with students about the consequences of bullying in a participatory manner. Communication strategy is planning the delivery of messages through various communication elements such as frequency, formality, content and communication channels so that the messages conveyed are easily received and understood and can change attitudes or behavior in accordance with communication objectives.