There is no single official number for “how many mass shootings” in Australia because different sources use different definitions and time frames.
Key points
Most academic and government work defines a mass shooting as an incident with at least four people shot (sometimes “killed,” sometimes “killed or injured”), not including acts of war or many historical massacres of Aboriginal people, which are often under‑recorded.
From Federation to the mid‑1990s, Australia experienced a small number of high‑fatality mass shootings, including 13 such incidents over the 18 years up to and including the 1996 Port Arthur massacre.
Since 1996 gun law reforms
After Port Arthur in 1996, Australia introduced the National Firearms Agreement, and studies find both the rate and deadliness of mass shootings declined sharply, though small‑scale firearm incidents still occur.
A commonly cited list using a “four or more casualties” definition records a few dozen mass shootings in total over Australia’s history, with only a small number since 2000 compared with the pre‑1996 period.
Example overall counts
Using the broader four‑casualty (dead or injured) definition, one public dataset lists 20‑plus mass shootings in Australia since 2000, including incidents such as the 2002 Monash University shooting, the 2014 Lindt Café siege, the 2018 Osmington familicide, and later events in Darwin, Bogie and Wieambilla.
If only incidents with four or more people killed are counted, the total is much smaller, dominated by events like Hoddle Street (1987), Strathfield (1991), Port Arthur (1996) and Osmington (2018).
How to interpret “how many”
Because counts change depending on whether:
- At least 4 killed vs at least 4 total shot are required.
- Suicides, familicides and gang incidents are included or excluded.
- Historical frontier massacres are counted separately.
Any precise number needs a definition; for current research or policy work, it helps to specify the period (for example, “since 1996”) and whether the threshold is “4 killed” or “4 killed or injured.”
