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 Iowa, manslaughter is categorized under Iowa Code Section 707 as either voluntary or involuntary manslaughter. Voluntary manslaughter occurs when someone intentionally causes the death of another person under circumstances that would cause a reasonable person to become emotionally or mentally disturbed. This does not include premeditated murder but may involve situations such as killing in the heat of passion. Involuntary manslaughter, on the other hand, is when an individual unintentionally causes the death of another person by acting recklessly or engaging in misdemeanor conduct that results in a fatality. This could include fatal accidents arising from DUIs or other negligent behaviors. Manslaughter in Iowa is considered a felony, and the penalties can be severe, including substantial prison time. The specific circumstances of the case, such as the presence of any aggravating factors, can influence the severity of the punishment.