The Kent State shootings (also known as the May 4 massacre and the Kent State massacre) resulted in the killing of four and wounding of nine unarmed college students by the Ohio National Guard, on the Kent State University campus. The shootings took place on May 4, 1970, during a peace rally opposing the expanding involvement of the Vietnam War into Cambodia by United States military forces as well as protesting the National Guard presence on campus. This incident marked the first time a student was killed in an anti-war gathering in United States history.

Twenty-eight National Guard soldiers fired about 67 rounds over 13 seconds, killing four students and wounding nine others, one of whom suffered permanent paralysis. Students Allison Krause, 19, Jeffrey Glenn Miller, 20, and Sandra Lee Scheuer, 20, died on the scene, while William Knox Schroeder, 19, was pronounced dead at Robinson Memorial Hospital in nearby Ravenna shortly afterward.

Krause and Miller were among the more than 300 students who gathered to protest the expansion of the Cambodian campaign, which President Richard Nixon had announced in an April 30 television address. Scheuer and Schroeder were in the crowd of several hundred others who had been observing the proceedings more than 300 feet (91 m) from the firing line; like most observers, they watched the protest during a break between their classes.

The fatal shootings triggered immediate and massive outrage on campuses around the country. It increased participation in the student strike that began on May 1. Ultimately, more than 4 million students participated in organized walk-outs at hundreds of universities, colleges, and high schools. The shootings and the strike affected public opinion at an already socially contentious time over the role of the United States in the Vietnam War.