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 Louisiana (LA), manslaughter is defined under Louisiana Revised Statutes Title 14:31. The state recognizes both voluntary and involuntary manslaughter. Voluntary manslaughter in Louisiana is a homicide which would be murder, but is committed in sudden passion or heat of blood immediately caused by provocation sufficient to deprive an average person of his self-control and cool reflection. Involuntary manslaughter, under Louisiana law, involves the killing of a human being by a person engaged in the commission of, or in an attempt to commit, any misdemeanor directly affecting the person, or without any intent to cause death or great bodily harm. Manslaughter is considered a felony in Louisiana and can result in severe penalties, including imprisonment. The specific circumstances of the case, such as the presence of aggravating factors, can influence the severity of the sentence. An attorney can provide more detailed information on how these laws may apply to specific cases and the potential defenses that may be available.