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 Kentucky, manslaughter is categorized into two degrees as defined by state statutes. First-degree manslaughter, under Kentucky law, is a Class B felony and occurs when a person intentionally causes another person's death under circumstances that would otherwise constitute murder, but the act is committed under the influence of extreme emotional disturbance. Second-degree manslaughter, a Class C felony in Kentucky, is when a person's death is caused by a defendant's wanton or grossly negligent act, such as operating a motor vehicle under the influence of alcohol or drugs. Kentucky does not use the terms 'voluntary' or 'involuntary' manslaughter, but the concepts are similar to first and second-degree manslaughter, respectively. Manslaughter in Kentucky is a serious felony offense and can result in substantial prison time upon conviction.