Involuntary manslaughter is a criminal offense defined as the unintentional killing (homicide) of another person as a result of criminal negligence, recklessness, or during the commission of a misdemeanor (driving while intoxicated), infraction (speeding), or a felony crime that was not inherently dangerous. Involuntary manslaughter is usually a felony offense and often includes significant jail or prison time as potential punishment.

Involuntary manslaughter laws vary from state to state and are generally located in a state’s statutes—often in the penal or criminal code.

In Washington State, involuntary manslaughter is addressed under the term 'Manslaughter' and is categorized into two degrees. Manslaughter in the first degree, covered under RCW 9A.32.060, occurs when a person recklessly causes the death of another person. This is a Class A felony, which can result in a life sentence, a fine of up to $50,000, or both. Manslaughter in the second degree, under RCW 9A.32.070, involves causing the death of another person through criminal negligence. This is considered a Class B felony, potentially leading to a maximum of 10 years in prison, a fine of up to $20,000, or both. The state does not require the intent to kill for a conviction of manslaughter; rather, it focuses on the recklessness or negligence of the individual's actions that led to the death. Additionally, Washington law recognizes that certain actions, even if not inherently dangerous, can lead to involuntary manslaughter charges if they result in someone's death, such as driving under the influence (DUI).