Overview

The Columbine High School massacre occurred on April 20, 1999, at Columbine High School in Columbine, Colorado. Two senior students, Eric Harris and Dylan Klebold, shot and killed 13 students and one teacher. Twenty people were injured by gunfire, and three others were injured while trying to escape. The attack ended when Harris and Klebold committed suicide.

Historical accounts describe the pair as having planned the attack for roughly a year. They intended it to be primarily a bombing, and launched a shooting attack after homemade bombs planted in the school failed to detonate. Their motive remains uncertain.

Legacy

Columbine was the deadliest mass shooting at a K-12 school in U.S. history until the Sandy Hook Elementary School shooting in December 2012, and the deadliest high school shooting until the 2018 attack at Marjory Stoneman Douglas High School. It is considered among the most infamous massacres in the United States and has become a byword for modern school shootings.

The event’s lasting impact is often described as the Columbine effect. It influenced school safety, policing tactics, and prevention methods including gun control and metal detectors. It also inspired copycat crimes, with some perpetrators imitating Harris and Klebold’s methods or outward styles. In later reporting on school shootings, the 1999 attack is frequently cited as a high-profile example.