<p>We conducted a preliminary evaluation of a US-based training focused on police-adolescent interactions to learn about opportunities and challenges, and to inform similar trainings in other police agencies. This was a sequential mixed-methods study, including a survey of 546 police personnel at pre-training and 339 personnel at post-training. Ten focus group sessions were subsequently conducted with 50 police. This study identified several lessons for improving police training on adolescent interactions, including the need for nuanced adolescent development content; inclusion of youth and police voices and knowledge; and practical, skills-based strategies. Police emphasized the importance of accessible mental health resources and referral options but noted cultural and structural barriers to fully implementing training principles. Lastly, state-level juvenile laws and policies frustrated participants and were noted as not discussed in sufficient depth in the training. Overall, findings demonstrate that training focused on police-adolescent interactions could better equip police personnel with a comprehensive understanding of the legal framework within which they operate, fostering better-informed and more effective policing practices. Lasting impact will require not only enhanced training but also supportive infrastructure and shifts in policing culture.</p>