Roughly a decade after the substantial spike in the middle and high school massacres that occurred in the '90s, we have now seen this disturbing phenomenon arise anew on American college campuses. Overall, these horrifying, high profile acts of violence on college campuses remain relatively rare, nevertheless, academic administrators are required to manage threats of violence on an increasingly regular basis. As colleges and universities face the realities of today's educational environment, preparing for an active shooter event has become a necessity. The mass shooting at the University of Texas at Austin in 1966 has been hailed as the first major college campus-shooting incident. Since then, years of active shooting training and protocol development and evolution has taken place. A description of four of the deadliest college campus shootings (University of Texas at Austin, Virginia Tech, Oikos University, and Umpqua Community College) and the progression of the related active shooter protocols is provided.