Northern Illinois University shooting: A gunman opens fire in a lecture hall of Northern Illinois University in DeKalb County, Illinois, resulting in six fatalities (including the gunman) and 21 injuries.

The Northern Illinois University shooting was a school shooting that took place on Thursday, February 14, 2008, at Northern Illinois University (NIU) in DeKalb, Illinois. Steven Kazmierczak, 27 years old and a 2006 NIU graduate, opened fire with a shotgun and three pistols in a crowd of students on campus, killing 5 students and injuring 17 more people, before fatally shooting himself.

A lecture hall or lecture theatre is a large room used for lectures, typically at a college or university. Unlike flexible lecture rooms and classrooms with capacities normally below one hundred, the capacity of lecture halls can sometimes be measured in the hundreds. Lecture halls frequently have tiered seating, with those in the rear sat higher than those at the front.

Northern Illinois University (NIU) is a public research university in DeKalb, Illinois, United States. It was founded as "Northern Illinois State Normal School" in 1895 by Illinois Governor John P. Altgeld, initially to provide the state with college-educated teachers. In addition to the main campus in DeKalb, it has satellite centers in Chicago, Naperville, Rockford, and Oregon, Illinois.

DeKalb County is a county located in the U.S. state of Illinois. As of the 2020 United States census, the population was 100,420. Its county seat is Sycamore. DeKalb County is part of the Chicago–Naperville–Elgin, IL–IN–WI Metropolitan Statistical Area.