School Shooting Facts: Causes, Prevention, and Laws

School shooting facts in the United States are harder to pin down than the headlines suggest, but the picture that emerges from the available research is consistent: incidents have climbed to record levels in the 2020s, the shooters are almost always students using guns taken from home, the damage to survivors lasts for years, and the policy response works in some places and fails in others. Here is what the data actually shows.

How Often School Shootings Happen

There is no single agreed-upon count, because there is no single agreed-upon definition. The K-12 School Shooting Database, the most inclusive source, has documented more than 2,380 school shootings in the United States from 1966 through mid-2026. It counts any incident in which a gun is fired, brandished with intent to harm, or a bullet strikes school property, regardless of time of day, motive, or whether anyone was hit.¹

CNN uses a narrower measure: incidents on K-12 or college grounds where at least one person other than the shooter was shot. By that count, there were at least 83 incidents in both 2023 and 2024, at least 78 in 2025, and at least 30 in the first half of 2026. Each year from 2021 through 2024 set a record since CNN began tracking in 2008.²

Everytown for Gun Safety, which tracks any discharge of a live round inside or onto school grounds, recorded 57 incidents with 25 deaths and 28 injuries in just the first five months of 2026.³ A Government Accountability Office report confirmed that the same year can produce very different totals depending on which database you consult, with the FBI’s active-shooter definition capturing only a subset of what broader trackers record.⁴

The Deadliest Attacks

A small number of mass-casualty events dominate public memory. The deadliest school shooting in U.S. history remains the 2007 attack at Virginia Tech, where 32 people were killed and 23 wounded. The 2012 shooting at Sandy Hook Elementary in Newtown, Connecticut, killed 27, including 20 first-graders. The 2022 attack at Robb Elementary in Uvalde, Texas, killed 21 — 19 of them children. The 2018 shooting at Marjory Stoneman Douglas High School in Parkland, Florida, killed 17. The 1999 attack at Columbine High School in Littleton, Colorado, killed 13.⁵

Among more recent events, a 14-year-old student killed two classmates and two teachers and wounded nine others at Apalachee High School in Winder, Georgia, in September 2024, using an AR-platform rifle. The suspect had been investigated by the FBI and local authorities a year earlier after anonymous online tips about school shooting threats, but no arrest was made at that time.⁶⁷

How School Shootings Fit Into Youth Gun Violence

Mass-casualty school attacks draw intense coverage, but the majority of gun violence affecting American children happens elsewhere. Federal data from the National Center for Education Statistics for the 2020–21 school year counted 2,436 youth homicides and 2,346 youth suicides nationwide, but only 11 school-associated homicides and six school-associated suicides. Historically, about 1% or fewer of all youth homicides, and under 1% of youth suicides, have taken place at school.⁸

Firearms are nonetheless the leading cause of death for American children and teens. More than 4,400 children and teens are shot and killed each year, and more than 17,000 are shot and wounded. For children under 13, 85% of gun homicide deaths occur in the home, and nearly 80% of child gun suicides involve a firearm belonging to a parent or relative.⁹

Schools that do experience gunfire are disproportionately in communities already affected by broader violence. Black students make up 15% of the K–12 population but 30% of the average population at schools affected by a fatal shooting, and between 2013 and 2021, 67% of incidents with available demographic data occurred at majority-minority schools.⁹

Who Commits School Shootings

Most school shooters are students at the school they target. A U.S. Secret Service study of 41 K-12 attacks from 2008 to 2017 found that the vast majority of attackers were male, 63% were white, and they ranged in age from seventh-graders to seniors. Most had been badly bullied, had a history of disciplinary trouble and recent absences, and more than three-quarters launched their attack after a specific incident with someone at the school.¹⁰

The National Institute of Justice reported in 2022 that between 92% and 100% of K-12 mass shooter perpetrators were actively suicidal before or during the attack. They commonly had histories of childhood trauma and antisocial behavior, though psychosis was present in only a minority. Many had signaled instability and an inability to cope through social media or other channels before acting.¹¹

How they obtain weapons is one of the most important findings in the research. Eighty percent of K-12 mass shooters stole their firearm from a family member, a sharply different pattern from mass shooters in other settings, where 77% purchase firearms legally. Handguns remain the most common weapon, though K-12 shootings involve semi-automatic assault-style weapons more often than shootings in other contexts.¹¹

The Secret Service concluded that there is “no clear profile of a school attacker” but that most incidents are preventable through identifying what investigators describe as a “constellation of behaviors and factors.” Many attackers were influenced by previous shootings, with Columbine, Virginia Tech, and Sandy Hook cited specifically.¹⁰

Warning Signs and the Role of Leaking

Perpetrators overwhelmingly signal their intentions before acting, a pattern researchers call “leaking.” Most share their plans with peers or on social media. The NIJ found that two-thirds of all mass shooting plots, including school incidents, are foiled through public reporting. The problem is that leaks often go unreported, either because peers do not recognize the seriousness of the statements or because they fear social consequences for reporting.¹¹

The Violence Project’s database of mass shooters from 1966 to 2025 found that 81% exhibited observable warning signs before an attack and 47% told someone about their plans. Common signs included increased agitation, social isolation, depressed mood, and mood swings.¹² Sandy Hook Promise’s Say Something Anonymous Reporting System, a 24/7 tip line operating in schools nationwide, reports more than 403,000 anonymous tips received, 19 planned school shootings prevented, and 1,269 confirmed young lives saved from suicide.¹³

What a Shooting Does to Survivors

The casualty counts capture only the people hit by bullets. Since 1999, more than 380,000 students have been exposed to firearm violence at school.¹⁴ An estimated 100,000 children attended a school where a shooting occurred in 2018 and 2019 alone.¹⁵

Research on youth living within five miles of a fatal school shooting found prescriptions for mental health medications rose by more than 25%, with increases across antidepressants, antipsychotics, and antianxiety drugs. The elevated use persisted for at least five and a half years, peaking at about three and a half years in. A sharp increase appeared even among youth with no prior history of psychotropic prescriptions.¹⁶

Academic consequences are similarly severe. Data from Texas public schools showed that in the two years after a shooting, students experienced a 12% increase in absent days, a 28% increase in chronic absenteeism, and more than double the likelihood of needing to repeat a grade.¹⁵

The long-term economic damage adds up. Students exposed to a school shooting during high school were 3.7% less likely to graduate, 9.5% less likely to enroll in college, and 15.3% less likely to earn a bachelor’s degree by age 26. By their mid-twenties, they were 6.3% less likely to be employed and earned roughly $2,780 (13.5%) less per year. Researchers estimated the reduction in lifetime earnings at approximately $115,550 per affected student, with the aggregate annual cost to society from lost earnings at $5.8 billion. Even shootings with no fatalities produced lasting damage comparable to what researchers observed among survivors of the 2011 Utøya massacre in Norway.¹⁵

What Works and What Doesn’t

Schools have spent billions on physical security. The evidence that it prevents shootings is thin and sometimes contradicts intuition.

Armed Guards

A Violence Project analysis of 133 school shootings from 1980 to 2019 found no significant reduction in injury rates when an armed guard was present. Shootings at schools with armed guards resulted in three times as many deaths on average, a finding researchers attribute partly to the possibility that armed officers may function as targets rather than deterrents for suicidal attackers. An FBI analysis of active shooter incidents from 2000 to 2013 noted that most are over within minutes, often before law enforcement can respond effectively.¹⁷

Despite these findings, Texas in 2023 mandated that every campus have at least one armed security officer, with per-officer costs estimated as high as $100,000. Tennessee allocated $140 million for armed school security the same year.¹⁷

Metal Detectors and Cameras

Results are mixed. While one study associated random metal detector searches with reduced weapon carrying, researchers have more broadly found them ineffective, and one analysis linked them to increased reports of serious violence in high schools. Security cameras were positively associated with higher incidences of weapon attacks in high schools, a pattern researchers suggest reflects the fact that schools already experiencing violence are more likely to install such equipment.¹⁸

A 2025 scoping review of empirical studies concluded that the overall evidence base for physical security preventing weapon carriage in schools is “weak” and “limited.” The one factor consistently associated with lower reports of serious violence was a high level of student engagement, defined as more than 50% of students feeling school is important.¹⁹

Active Shooter Drills

Roughly 95% of U.S. public K-12 schools conduct active shooter or lockdown drills, and at least 40 states require them. There is no conclusive research showing they prevent shootings or protect people during an attack.²⁰

Research analyzing nearly 28 million social media posts from communities where drills took place found a 42% increase in stress and anxiety and a 39% increase in depression in the 90 days following a drill. Effects were largest for high schoolers (52% increase in stress and anxiety) and middle schoolers (55% increase in depression). Elementary students experienced a 28% increase in stress and anxiety. Effects extended to parents and lasted at least three months.²⁰

A 2025 report from the National Academies of Sciences, Engineering, and Medicine found fewer than two dozen empirical studies on the mental health effects of drills exist, most relying on weak research designs. Some showed improved confidence in emergency response; others showed increased fear, and a significant subset found that students’ perceptions of school safety actually decreased after participating. There are currently no national standards governing how drills should be conducted.²¹²²

Threat Assessment

The approach with the strongest evidence behind it is behavioral threat assessment, where multidisciplinary teams of school officials, mental health professionals, and law enforcement evaluate reported concerns about a student. As of April 2024, 85% of U.S. schools reported having a threat assessment team, and 45 states have established some form of threat assessment policy.²³

The most studied framework, the Comprehensive School Threat Assessment Guidelines (CSTAG), discourages zero-tolerance policies and profiling in favor of mental health supports and proactive intervention. Randomized controlled studies found that implementing CSTAG led to reductions in long-term suspensions and bullying infractions and increased provision of counseling. Students in CSTAG schools were significantly more likely to receive counseling and parent conferences rather than suspension or transfer.²³

Implementation is uneven. Only 7 of the 20 states that mandate school threat assessments require data to be collected and reported, and no state requires those data to be made public. Investigations have found inconsistent implementation, lack of expertise on assessment teams, and racial disparities in referrals, with Black students and students with disabilities disproportionately affected. Schools frequently lack the counselors and psychologists needed to support the process.²³

Federal Law

Two primary federal statutes address firearms and schools. The Gun-Free School Zones Act of 1990 makes knowing possession of a firearm in a school zone a federal crime. The original version was struck down by the Supreme Court in United States v. Lopez (1995) as exceeding Congress’s commerce power, but the law was amended to apply to firearms that have moved in interstate commerce and remains in effect.²⁴ The Gun-Free Schools Act (20 U.S.C. § 7961) separately requires any state receiving federal education funds to have a law mandating at least one year of expulsion for students who bring a firearm to school, along with referral to the criminal justice system.²⁵

The most significant recent federal action is the Bipartisan Safer Communities Act, signed on June 25, 2022. It was the first major federal gun safety legislation in roughly three decades and addressed school shootings through several mechanisms:

Enhanced background checks for buyers under 21, including checks of juvenile criminal and mental health records. As of mid-2024, over 260,000 checks had been completed and 800 firearm purchases had been blocked.
$1.3 billion for school safety, including $1 billion for the Stronger Connections grant program (awarded to over 2,100 communities), $300 million for school safety interventions, and $50 million for before- and after-school programs. More than 3,500 schools expanded intervention teams and 2,300 formed new ones.
$1 billion over five years to hire and train 14,000 new school-based counselors, psychologists, and social workers.
$750 million for state crisis intervention programs, including extreme risk protection orders.
New federal criminal charges for firearm trafficking and straw purchasing, resulting in 525 defendants charged in 280 cases.

The law also closed the so-called “boyfriend loophole,” prohibiting individuals convicted of misdemeanor domestic violence in a dating relationship from possessing firearms, and enhanced the 988 Suicide Prevention Lifeline, reducing average answer speeds from over two minutes to 40 seconds.²⁶²⁷

Red Flag Laws and Secure Storage

Two state-level interventions map directly onto what the shooter research shows.

Extreme Risk Protection Orders

As of early 2025, 21 states and the District of Columbia had laws allowing courts to temporarily remove firearms from individuals deemed a serious risk to themselves or others. (Everytown counts 22 states, reflecting slight differences in what qualifies.) In several states, educators and school administrators can file petitions. Between 1999 and 2023, more than 49,000 ERPO petitions were filed across 19 states and Washington, D.C. Judges granted temporary orders in more than 90% of cases, and 77% of subsequent hearings resulted in the order being extended.²⁸

A study of ERPO cases from six states found that 10% of all petitions were in response to threats of killing three or more people, and the most common target for those threats was K-12 schools. Judges granted 93% of temporary orders in those cases.²⁹ RAND’s assessment classifies the overall evidence for the effect of ERPOs on mass shootings as “inconclusive,” partly because the laws are too recent for robust population-level analysis. The evidence is stronger that they reduce suicides, with studies in Connecticut and Indiana estimating roughly one suicide prevented for every 10 orders granted, and California data suggesting one for every 22.²⁸

Secure Storage

Because 75 to 80% of K-12 school shooters obtain their weapon from their own home or a relative’s home, secure firearm storage is one of the most direct interventions available.¹¹³⁰ Twenty-six states have negligent storage laws holding adults criminally liable when children gain access to unsecured firearms; another nine impose liability for recklessly providing firearms to children.³¹

Research links these laws to lower rates of gun suicides, homicides, and unintentional shootings among young people, with the strongest storage requirements producing the greatest benefits.³² Storing firearms and ammunition securely has been associated with a 78% lower risk of self-inflicted firearm injuries and an 85% lower risk of unintentional injuries in children.³⁰ The evidence for the specific effect of these laws on mass shootings remains inconclusive.³¹

What Accountability Looks Like After an Attack

The 2022 Uvalde shooting, which killed 19 children and two teachers at Robb Elementary School, became a case study in both law enforcement failure and the slow path to accountability. A Department of Justice critical incident review found broad breakdowns in leadership, decision-making, tactics, and training. Responding officers retreated after initial gunfire and began treating the situation as a barricaded-subject scenario rather than an active shooter event. Thirty-three students and three teachers were trapped in a classroom with the gunman for over an hour while 376 law enforcement officers from multiple agencies gathered outside. There was a 77-minute delay between the arrival of the first officers and the confrontation that ended the threat.³³³⁴

A Texas House investigative committee separately determined that “systemic failures and egregious poor decision making” occurred, citing lack of clear leadership, ineffective communication, and failure to follow active-shooter training protocols. The school had an active shooter policy, but a “culture of complacency” had set in regarding basic security practices like locking doors.³⁴

Uvalde CISD Police Chief Pete Arredondo was fired approximately three months after the shooting. In June 2024, a grand jury indicted him on 10 felony counts of abandoning or endangering a child, each carrying up to two years in jail. A former district officer, Adrian Gonzales, was indicted on the same charges. In December 2024, a judge refused to dismiss the charges against Arredondo, and a trial date was set for October 2025. Arredondo has pleaded not guilty.³⁵³⁶

In civil litigation, the city of Uvalde and Uvalde County each settled with victims’ families for $2 million in insurance payments. The settlements included provisions to rebuild the police department, establish May 24 as an annual day of remembrance, design a permanent memorial, and continue mental health services. Families filed a separate lawsuit against the 92 individual Texas Department of Public Safety officers present at the scene. As of mid-2026, the Texas Supreme Court had rejected a related survivors’ lawsuit, though litigation against DPS officers and other defendants continues.³⁷³⁸

1
K-12 School Shooting Database. Methodology
2
CNN. School Shootings Fast Facts
3
Everytown for Gun Safety. Gunfire on School Grounds
4
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5
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6
NPR. Apalachee High School Georgia Shooting Victims
7
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8
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9
Everytown for Gun Safety. The Impact of Gun Violence on Children and Teens
10
PBS NewsHour. Secret Service Study Explores School Shooter Warning Signs
11
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12
The Violence Project. Mass Shooter Database
13
Sandy Hook Promise. Say Something
14
University of Washington. Examining Mental Health and Recovery Following School Shootings
15
Stanford Institute for Economic Policy Research. Surviving a School Shooting
16
Northwestern University Institute for Policy Research. The Mental Health Effects of School Shootings
17
The Trace. Guns, Armed Guards, and School Shootings
18
U.S. House of Representatives. Research on School Security Measures
19
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20
Everytown for Gun Safety. The Impact of Active Shooter Drills in Schools
21
National Library of Medicine. Active Shooter Drills in Schools
22
American Psychological Association. Active Shooter Drills and Safety
23
Learning Policy Institute. Behavioral Threat Assessments
24
American Bar Association. United States v. Lopez
25
Office of the Law Revision Counsel. 20 U.S.C. § 7961
26
U.S. Department of Justice. Fact Sheet: Two Years of the Bipartisan Safer Communities Act
27
The White House. A Report on the Implementation of the Bipartisan Safer Communities Act
28
RAND Corporation. Extreme Risk Protection Orders
29
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30
University of Michigan Firearm Injury Prevention. School Safe Storage
31
RAND Corporation. Child Access Prevention
32
Everytown for Gun Safety. Secure Storage or Child Access Prevention Required
33
U.S. Department of Justice. Critical Incident Review of the Robb Elementary Shooting
34
Texas Tribune. Law Enforcement Failure in Uvalde Shooting Investigation
35
Texas Tribune. Uvalde School Shooting Police Chief Arredondo Indictment
36
PBS NewsHour. Judge Refuses to Drop Criminal Charges Against Former Uvalde Schools Police Chief
37
Houston Public Media. Uvalde Families Sue Texas DPS, Settle With City and County
38
The New York Times. Uvalde Lawsuit Settlement