In criminal law, culpability, or being culpable, is a measure of the degree to which an agent, such as a person, can be held morally or legally responsible for action and inaction. It has been noted that the word culpability "ordinarily has normative force, for in nonlegal English, a person is culpable only if he is justly to blame for his conduct". The guilt principle requires that in order to convict a person it is necessary to ascertain his voluntary or reckless behaviour, Strict Liability being prohibited.

Culpability descends from the Latin concept of fault (culpa), which is also the origin of the phrase, mea culpa.

The concept of culpability is intimately tied up with notions of agency, freedom, and free will. All are commonly held to be necessary, but not sufficient, conditions for culpability.

A person is culpable if they cause a negative event and
(1) the act was intentional;
(2) the act and its consequences could have been controlled (i.e., the agent knew the likely consequences, the agent was not coerced, and the agent overcame hurdles to make the event happen); and
(3) the person provided no excuse or justification for the actions.

From a legal perspective, culpability describes the degree of one's blameworthiness in the commission of a crime or offense. Except for strict liability crimes, the type and severity of punishment often follow the degree of culpability. "Culpability means, first and foremost, direct involvement in the wrongdoing, such as through participation or instruction", as compared with responsibility merely arising from "failure to supervise or to maintain adequate controls or ethical culture".

Modern criminal codes in the United States usually make distinct four degrees of culpability.

Legal definitions of culpability, verbatim from the Pennsylvania Crimes Code, are:

In short: