There are two principal types of manslaughter under California law: voluntary and involuntary.

Voluntary manslaughter: Voluntary manslaughter laws apply to killings that take place during a sudden quarrel or in the heat of passion. This means that the killing was provoked, driving the defendant to act rashly and under the influence of intense emotions that obscured their reasoning or judgment. To satisfy the criteria for voluntary manslaughter as opposed to murder, the provocation has to be such that it would cause an average person to react emotionally.

Involuntary manslaughter: Involuntary manslaughter is an unlawful but unintentional killing that takes place during the commission of either an unlawful act (not a felony) or a lawful act that involves a high risk of harm or death. In the latter instance, the act must have been committed without proper caution or circumspection.