This chapter covers the challenges police face when encountering people with mental illnesses and neurodevelopmental disabilities. As first responders, police have many duties, including providing emergency assistance, responding to crime complaints, and handling those experiencing mental health crises. Police report having regular interactions with individuals with mental illnesses and disabilities, yet most report not receiving the proper training to handle these interactions confidently. Many individuals with mental illnesses and disabilities also reported dissatisfaction during police encounters, including excessive force. This chapter covers the training and programs that improve interactions and outcomes, including de-escalation training and co-response teams. The chapter concludes with considerations and recommendations from experts in the field to improve the experiences of police and those with mental illnesses and disabilities during these encounters.