While body-worn cameras (BWCs) are increasingly becoming commonplace in police organizations, researchers and policymakers still know little about their implementation in the field and the factors related to their actual use. Using data collected from 146,601 incidents in Phoenix, Arizona, the present study examines the prevalence and correlates of BWC activation. In doing so, we examine the impact of incident-level factors, officer characteristics, neighborhood context, and changes in BWC activation policy on whether an officer who is assigned to wear a BWC activates their camera during a police-citizen contact. Cross-classified models are used to simultaneously assess the influence of factors at multiple levels of explanation. Our analysis suggests that a wide variety of individual, situational, organizational, and neighborhood factors are related to an officer’s decision to activate their camera. BWC policy that confines, structures, and checks officer activation has a robust impact on an officer’s decision to activate their BWC.