Although mass shootings have fueled calls for large-scale changes in gun ownership and concealed carry legislation over the past thirty years, few studies have evaluated whether permissive gun policies actually deter mass shootings, and none have determined if their effects are the same on firearms homicide in general. This study examines the impact of household gun ownership and concealed carry legislation on annual counts of mass shootings and firearms homicides in the United States from 1991 to 2016. Negative binomial regressions with fixed effects and generalized estimating equations (GEE) indicate that mass shootings disproportionately occur in states with higher levels of gun ownership, while firearms homicide rates are higher in permissive concealed carry states. As the two crimes do not respond to changes in gun ownership and concealed carry legislation in the same way, lawmakers must contextualize mass shootings as a small, unique part of overall gun violence when considering policy interventions.