PurposeKnowledge about the prevalence and impact of Adverse Childhood Experiences (ACEs) is pivotal to trauma-informed approaches, yet the impact of ACEs training is rarely investigated. This study reports a qualitative investigation of police perceptions of ACEs training in relation to conceptualisations of ACEs and trauma-informed working, practical applications of ACE knowledge and service-level support.Design/methodology/approachFour focus groups were conducted with 29 police officers, who had participated in an ACEs-awareness training. Based on the qualitative data, themes were generated using reflexive thematic analysis (Braun and Clarke, 2019).FindingsAnalysis generated seven themes, conceptualised into three domains of conceptual understanding, police culture and operationalising ACEs.Research limitations/implicationsThe sample is limited to Scottish police officers and is ethnically non-diverse. Further evaluation of higher quality interventions is warranted.Practical implicationsThe study highlighted that a lack of conceptual framework, officer concerns and police culture may present barriers to officers incorporating ACEs knowledge into their day-to-day work. Future trainings should address these issues to achieve maximum benefits.Originality/valueTo the authors’ knowledge, this is the first in-depth qualitative study of police officers' perceptions of ACEs training. Focus groups facilitated the expression of cultural norms. The results provide insight into tailoring trauma-informed interventions in police in future, as well as raising broader service-level issues.