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 Delaware, manslaughter is defined under Title 11, Section 632 of the Delaware Code. The state recognizes both voluntary and involuntary manslaughter. Voluntary manslaughter occurs when a person intentionally kills another in the heat of passion or while under extreme emotional disturbance for which there is a reasonable explanation or excuse. The reasonableness of the explanation or excuse is determined from the viewpoint of a person in the defendant's situation under the circumstances as the defendant believed them to be. Involuntary manslaughter in Delaware involves the unintentional killing of another person due to criminal negligence or during the commission of an unlawful act that is not a felony. Manslaughter in Delaware is considered a felony, and the penalties upon conviction can include a lengthy prison term. The specific circumstances of the offense, such as the presence of any aggravating factors, can influence the severity of the punishment.