Several decades before police use of deadly force emerged as an area of scholarly inquiry, US police began developing handgun training and certification programs that were focused narrowly on marksmanship proficiency. Important characteristics associated with contemporary training approaches, such as tactics for high-risk encounters and judgment in using deadly force, were not prevalent before the 1990s. Entities external to the police academies and departments that provide this training – such as training commissions, accrediting bodies, professional associations and the federal courts – have had important impacts upon the content and delivery of this training. Most of this influence has been relatively recent, however, and the literature reveals the broad latitude that police exercise in the nature and extent of deadly force training that today subsumes handgun training. Highlighting key findings from that literature, we critically examine the highly differential approaches used by US police. This latitude is problematic in that it accommodates all but the most vacuous approaches and thus poses serious questions about police performance in high-risk encounters where officers reasonably may use or threaten to use deadly force. This is a critical matter nationally, which leads us to propose a new research and evaluation agenda focused on generating meaningful empirical information for use by decision-makers responsible for policy and practice. The goal of such future efforts would be to maximize the safety, appropriateness and effectiveness of police action during high-risk encounters, some of which will involve the use or threatened use of deadly force.