On-officer video camera (OVC) technology in the field of policing is developing at a rapid pace. Large agencies are beginning to adopt the technology on a limited basis, and a number of cities across the United States have required their police departments to adopt the technology for all first responders. Researchers have just begun to examine its effects on citizen complaints, officers' attitudes, and street-level behavior. To date, however, there is no research examining how departmental policy and assignment of officers to a camera program affect officer behavior and opinions of the cameras. Policy and assignment have the potential to impact how officers react to the technology and can affect their interactions with citizens on a daily basis. This study measures camera activations by line officers in the Mesa Police Department during police-citizen encounters over a ten-month period. Data from 1,675 police-citizen contacts involving camera officers were subject to analysis. Net of controls (i.e., the nature of the crime incident, how it was initiated, officer shift, assignment, presence of bystanders and backup, and other situational factors), the bivariate and multivariate logistic regression analyses were used to examine how departmental policy (mandatory versus discretionary activation policy) and officer assignment (voluntary versus mandatory assignment) affected willingness to activate the cameras, as well as officer and citizen behavior during field contacts.