Emergency department (ED) use for behavioral-health-associated diagnoses has steadily increased in adult and pediatric populations, accounting for 1 out of every 8 ED visits. The increase in pediatric behavioral health ED visits, combined with limited resources for treatment, has created a challenge for EDs faced with extended boarding and constant observation of this population. The generalized behavioral health guidelines used at the practice site have not been adapted for the pediatric population. This project focused on providing age- and developmentally appropriate best practice guidelines for children under constant observation in the children's emergency department (CED) using Havelock's theory of planned change as the framework. Practice in the CED was compared to best practice recommendations identified in the literature and community standards including workflow, defined roles and responsibilities, addressing the needs of the parent/guardians, and defined outcomes. These best practices were incorporated in a guideline developed to provide age- and developmentally appropriate recommendations. An expert panel comprising the behavioral health nurse manager and children's emergency department nurse manager reviewed the guideline using the AGREE II tool, and the guideline was revised based on the composite results from the 6 domains in the AGREE II tool. Based on these composite results and panel feedback, domain 5 was revised to include an auditing and monitoring plan. In addition to improving the safety and care for the CED patient population, this project also serves to increase awareness of the topic while emphasizing on the need for additional research and evidence-based practice focused on pediatric behavioral health patients.