How has Black Lives Matter (BLM) influenced police lethal force? An event study design finds census places with early BLM protests experienced a 10% to 15% decrease in police homicides from 2014 through 2019, around 200 fewer deaths. This decrease was prominent when protests were large and frequent. Potential mechanisms behind the reduction include police agencies obtaining body-worn cameras to curtail force and a so-called ‘Ferguson effect.’ Fewer property crime arrests, but more reported murders, were associated with local protests, yet the property crime clearance rate fell.