The documentary film explores what Moore suggests are the primary causes for the Columbine High School massacre in 1999 and other acts of gun violence.

He focuses on the background and environment in which the massacre took place and some common public opinions and assumptions about related issues.

[7][8][9][10] In Moore's discussions with various people—including South Park co-creator Matt Stone, the National Rifle Association's president Charlton Heston, Oklahoma City bombing suspect James Nichols, and musician Marilyn Manson—he seeks to explain why the Columbine massacre occurred and why the United States' violent crime rate (especially concerning crimes committed with firearms) is substantially higher than those of other nations.

Later investigations showed that this was based on mistaken recollections, and Glenn Moore of the Golden Police Department concluded that they were absent from school on the day the attack took place.

He suggests that this might have very little educational value and the people he interviews generally agree, noting how Harris and Klebold led introverted lifestyles and had careless attitudes towards the game, and that nobody thought twice about it.

Moore suggests a culture of fear created by the government and the media leads Americans to arm themselves, to the advantage of gun-making companies.

"[15] The Boston Review called this scene a fabrication, [T]he bank doesn't ordinarily hand over guns to customers.

[17] About 20 minutes into the film, the Beatles song "Happiness Is a Warm Gun" plays during a montage in which footage of the following is shown: Early in the film, Moore links the violent behavior of the Columbine shooters to the presence of a large defense establishment manufacturing rocket technology in Littleton.

It is implied that the presence of this facility within the community, and the acceptance of institutionalized violence as a solution to conflict, contributed to the mindset that led to the massacre.

Moore conducts an interview with Evan McCollum, Director of Communications at a Lockheed Martin plant near Columbine, and asks him: So you don't think our kids say to themselves, 'Dad goes off to the factory every day, he builds missiles of mass destruction.'

What's the difference between that mass destruction and the mass destruction over at Columbine High School?McCollum responds: I guess I don't see that specific connection because the missiles that you're talking about were built and designed to defend us from somebody else who would be aggressors against us.After the release of the film, McCollum clarified that the plant no longer produces missiles (the plant manufactured parts for intercontinental ballistic missiles with a nuclear warhead in the mid-1980s), but rockets used for launching satellites: I provided specific information to Moore about the space launch vehicles we build to launch spacecraft for NASA, NOAA, the Dept.

[18]The film cuts to a montage of American foreign policy decisions, with the intent to counter McCollum's statement by citing examples of how the United States has frequently been the aggressor nation.

The following is a transcript of the onscreen text in the Wonderful World segment: The montage ends with handheld-camera footage of United Airlines Flight 175 crashing into the South Tower of the World Trade Center on September 11, 2001, the audio consisting solely of the emotional reactions of the witnesses, recorded by the camera's microphone.

In regards to the film, Farber states "Moore's thesis, which he later elaborated in Fahrenheit 9/11, is that the fear-mongering that permeates American society contributes to our epidemic of gun violence".

[23] As a humorous retort to this, Stone and Parker portrayed Moore as "a gibbering, overweight, hot-dog-eating buffoon" who ultimately commits a suicide bombing against the protagonists in their 2004 film, Team America: World Police.

Moore ends this segment with gun-related-deaths-per-year statistics of the following countries: The American Prospect published a piece by Garance Franke-Ruta criticizing the film for ignoring the role that municipal governance plays in crime in the United States, and ignoring African-American urban victims of violence while focusing on the unusual events of Columbine.

"[25] Moore takes two Columbine survivors, Mark Taylor and Richard Castaldo (along with Brooks Brown, who remains unidentified during the segment), to the Troy, Michigan headquarters of American superstore Kmart to claim a refund on the bullets still lodged in their bodies, which were purchased by the perpetrators at a Kmart store.

Moore then decides to visit a Kmart in nearby Sterling Heights, where they purchase the store's entire supply of ammunition, and the three return to the company's headquarters the following day with several members of the local media.

[35] Michael Wilmington of the Chicago Tribune wrote, "It's unnerving, stimulating, likely to provoke anger and sorrow on both political sides—and, above all, it's extremely funny.

Scott of The New York Times wrote, "The slippery logic, tendentious grandstanding, and outright demagoguery on display in Bowling for Columbine should be enough to give pause to its most ardent partisans, while its disquieting insights into the culture of violence in America should occasion sober reflection from those who would prefer to stop their ears.

Moore was both applauded and booed at the Academy Awards on March 23, 2003, when he used his acceptance speech as an opportunity to proclaim his opposition to the presidency of George W. Bush and the United States-led invasion of Iraq, which had begun just a few days earlier.

The film was released on DVD and Blu-ray in a digital restoration with supplementary features by the Criterion Collection in June 2018.