Manslaughter is the unlawful killing or homicide of a human being without the premeditation or malice (malice aforethought) required for the criminal offense of murder.

Many states have two types of manslaughter: (1) voluntary manslaughter—the defendant intended to kill the victim, but did so in self-defense, or in the heat of passion and without premeditation, or the defendant was insane and did not understand that the killing was wrong; and (2) involuntary manslaughter—the defendant negligently or recklessly caused the death of another person—such as when a person is intoxicated while operating a motor vehicle and causes an accident that results in the death of another person.

Some states do not have separate criminal offenses for voluntary and involuntary manslaughter—these states may have the offense of manslaughter and identify certain aggravating factors that may enhance the penalties upon a conviction for manslaughter.

Manslaughter is a felony offense and may be punished by a lengthy prison term. Manslaughter laws are generally located in a state's statutes—often in the penal or criminal code.

In Arizona, manslaughter is defined under Arizona Revised Statutes § 13-1103. The state recognizes manslaughter as a class 2 felony, which can result in a lengthy prison sentence. Arizona law does not explicitly categorize manslaughter as 'voluntary' or 'involuntary.' Instead, it outlines circumstances under which a person can be charged with manslaughter, such as recklessly causing the death of another person, committing second-degree murder upon a sudden quarrel or heat of passion, or assisting in a suicide, among others. Manslaughter in Arizona also covers situations where a person's reckless behavior, including operating a vehicle under the influence, leads to the death of another. The penalties for manslaughter in Arizona are severe and can include prison time, fines, and other consequences. An attorney can provide specific guidance on how these laws may apply to individual cases.