The present study is the first to determine reasons for missing interventions by educational professionals in hate speech incidents at school using the bystander intervention model, which describes a five-stage, cognitive deliberation process that precedes a possible intervention. 46 episodic interviews with students (n = 21), teachers (n = 16) and other educational school staff (n = 9) from Berlin and Brandenburg were evaluated. The analysis of the qualitative data material shows that reasons why no interventions take place in response to hate speech can be found at all five stages of the deliberation process: school staff cannot always perceive hate speech (1), and in some cases does not interpret it as worthy of intervention, e.g., referring to violent or juvenile language norms (2), sometimes does not accept responsibility, especially in the case of online hate speech (3), assesses own intervention skills as insufficient (4) or weighs up the costs and benefits of a possible intervention and therefore decides against an intervention action (5). The results indicate that raising awareness to hate speech and its consequences for those involved, e.g., through education, could strengthen the assumption of responsibility. The qualitative data material also put out the school staff’s wishes for training and further education opportunities. Furthermore, it indicates demands for more capacities in everyday school life to be able to intervene appropriately in hate speech events.