Assessment, diagnosis and treatment of preschoolers with post-traumatic stress disorder (PTSD) is an understudied domain, and translational research assisting practitioners in the real-life identification of PTSD symptoms is critical. The current study examined therapists’ behavioural notes of 56 children participating in a 10-session intervention following exposure to intimate partner violence. The notes were analysed to identify themes in children's expression of re-experiencing symptoms and examine the overlap of these symptoms with emotional and behavioural dysregulation. The majority of re-experiencing in the therapeutic context was verbally expressed (e.g. storytelling), but physical re-enactments had the most overlap with in-session emotional and behavioural dysregulation. Session content that addressed who is to blame for the violence, characteristics about families, and conflict resolution techniques elicited particularly high levels of re-experiencing symptoms. The findings indicate that re-experiencing symptoms are both evident and recognisable in the therapeutic context, and practitioners should be careful not to misdiagnose children with behaviour disorders when dysregulation is explained by the presence of re-experiencing symptoms. Potential safety mechanisms that can be put in place to support young children during “high triggering” sessions are also considered.