This study examined 64 school shooters who committed multi-victim attacks in the United States during the years 1966 through 2015. Results include demographic analysis of age, venues of attack, racial/ethnic identity, magnitude of attacks, and frequency of perpetrator suicide. Data is provided for the sample as a whole, as well as for different time periods to highlight trends over time. Notable results include numerous changes in post-Columbine attacks, including greater age range of perpetrators, more perpetrators who are not white males, increased fatalities, and increased suicide rates. The article was published in the Journal of Campus Behavioral Intervention (J-BIT) 4 (2016) 5-17. It is reprinted here with permission of the National Behavioral Intervention Team Association (NaBITA).