List of mass shootings in the United States in 2023

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Mass shootings in the contiguous United States in 2023^[1]

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Mass shootings in Hawaii in 2023

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Mass shootings in Puerto Rico in 2023

This is a list of mass shootings that took place in the United States in 2023. Mass shootings are incidents in which several people are victims of firearm-related violence, specifically for the purposes of this article, a total of four or more victims. A total of 754 people were killed and 2,443 other people were injured in 604 shootings.

Several different inclusion criteria are used; there is no generally accepted definition.^[2][3] Gun Violence Archive, a nonprofit research group that tracks shootings and their characteristics in the United States, defines a mass shooting as an incident in which four or more people, excluding the perpetrator(s), are shot in one location at roughly the same time.^[4] The Congressional Research Service provides a definition of four or more killed.^[2][5] The Washington Post and Mother Jones use similar definitions, with the latter acknowledging that their definition "is a conservative measure of the problem", as many shootings with fewer fatalities occur.^[6][7] The crowdsourced Mass Shooting Tracker project applies the most expansive definition: four or more shot in any incident, including the perpetrator.^[8][9]

A 2019 study of mass shootings published in the journal Injury Epidemiology recommended developing "a standard definition that considers both fatalities and nonfatalities to most appropriately convey the burden of mass shootings on gun violence."^[10] The authors of the study further suggested that "the definition of mass shooting should be four or more people, excluding the shooter, who are shot in a single event regardless of the motive, setting or number of deaths."^[11]

Definitions generally exclude consideration of the number of persons targeted with lethal intent, perhaps with degraded accuracy from a greater distance, who escape injury from bullets or bullet spall, regardless of injury sustained while evading live gunfire, or medical complications resulting from those injuries (such as infection, concussion, stroke, or PTSD) further down the road.

• Stanford University MSA Data Project: three or more persons shot in one incident, excluding the perpetrator(s), at one location, at roughly the same time. Excluded are shootings associated with organized crime, gangs or drug wars.^[12]
• Mass Shooting Tracker: four or more persons shot in one incident, at one location, at roughly the same time.^[13][9]
• Gun Violence Archive/Vox: four or more shot in one incident, excluding the perpetrators, at one location, at roughly the same time.^[14][15]
• Mother Jones: three or more shot and killed in one incident at a public place, excluding the perpetrators. This list excludes all shootings the organization considers to be "conventionally motivated" such as all gang violence and armed robberies.^[7]
• The Washington Post: four or more shot and killed in one incident at a public place, excluding the perpetrators.^[6]
• ABC News/FBI:^{[n 1]} four or more shot and killed in one incident, excluding the perpetrators, at one location, at roughly the same time.^[16]
• Congressional Research Service: four or more shot and killed in one incident, excluding the perpetrators, at a public place, excluding gang-related killings and those done with a profit-motive.^[17]

Only incidents considered mass shootings by at least two of the above sources are listed below. Many incidents involving organized crime and gang violence are included.

All definitions can be exceeded with a single shotgun blast into a target cluster at short range. Mass shootings do not require multiple gunshots.

For statistical purposes, armed accomplices are likely to be classified as perpetrators, even if later analysis determines that the accomplice never discharged a firearm. Bystanders struck by bullets fired in self defense by another bystander would potentially be classified as victims of a mass shooting, while a bystander firing in self defense who injures or kills another bystander would almost certainly not be classified as a perpetrator. The classification of a bystander struck by police while attempting to take out a believed perpetrator falls into a gray zone.