What Are Crimes Against Humanity?

Reviewed 18 September 2026. This is an evergreen explainer; case-specific legal findings should be checked against the newest authoritative source.

In short: How crimes against humanity differ from war crimes and genocide, and what “widespread or systematic attack against a civilian population” means.

Crimes against humanity are a category of international crimes directed against civilian populations. Unlike war crimes, they do not require an armed conflict. Unlike genocide, they do not require proof of an intent to destroy a protected group as such. Their legal structure is different, even when the same violent act could potentially fall into more than one category.

The contextual element is crucial

Under the Rome Statute, crimes against humanity involve specified acts committed as part of a widespread or systematic attack directed against a civilian population, with knowledge of the attack. “Attack” in this context does not simply mean a military airstrike; it refers to a course of conduct involving multiple acts against civilians pursuant to or in furtherance of a State or organisational policy under the Statute’s framework.

What acts can qualify?

The listed acts include murder, extermination, enslavement, deportation or forcible transfer, imprisonment or severe deprivation of liberty, torture, several forms of sexual violence, persecution, enforced disappearance, apartheid and other inhumane acts meeting the legal threshold. The existence of one of these acts is not enough by itself—the broader contextual elements must also be proved.

Widespread and systematic are not casual adjectives

Courts analyse scale, pattern, organisation, repetition and the relationship between individual acts and the broader attack. “Widespread” generally concerns large-scale conduct or the number of victims; “systematic” concerns organised or patterned conduct. The precise legal test depends on the governing statute and jurisprudence.

No war is required

A major distinction from war crimes is that crimes against humanity can be committed during war or peace. The crime is built around the nature of the attack on a civilian population rather than the existence of an armed conflict.

The same event can engage several legal categories

An act of killing could, depending on the facts, be an ordinary domestic crime, a war crime, a crime against humanity and/or an act contributing to genocide. These categories are not mutually exclusive, but each has elements that must be proved independently.

Allegation, charge and conviction are different stages

International reporting should identify whether an institution has merely opened an investigation, found reasonable grounds, issued an arrest warrant, confirmed charges or delivered a final judgment. Those stages involve different evidentiary standards and should not be collapsed into one claim of guilt.

Frequently asked questions

Do crimes against humanity only happen during war?

No. Armed conflict is not a required element.

Is every mass killing a crime against humanity?

Not automatically. The contextual requirements—such as a widespread or systematic attack directed against civilians—must be established.

Can one act be both a war crime and a crime against humanity?

Yes, if the separate legal elements of both offences are satisfied.