The last few years have seen a mental health crisis for children and young people in the UK, with more young people presenting to services at crisis point. Young people have reported that there is a general lack of support before reaching the point of crisis and police forces in the UK have seen a rise in callouts related to youth mental health problems. We provide an overview of the evidence for joint responses from police and mental health services and highlight the importance of including people with lived experience in the development of crisis services. Most of the available data relates to interventions for adults, with very few studies including children and young people. We outline a new study in the UK aiming to evaluate a joint response for young people experiencing a mental health crisis. Whilst resources for children and young people’s crisis services remain limited, joint response models with police forces can help to provide much needed intervention.