In criminal law, an acquittal is the legal result of a verdict of not guilty, or some similar end of the proceeding that terminates it with prejudice without a verdict of guilty being entered against the accused. The opposite result is a conviction.

In the common law tradition, an acquittal formally certifies the innocence of the accused, as far as the criminal law is concerned. Under the rules of double jeopardy and autrefois acquit, an acquittal operates to bar the retrial of the accused for the same offense. The effect of an acquittal on criminal proceedings is the same whether it results from a jury verdict, or whether it results from the operation of some other rule that discharges the accused.

An acquittal, while conclusive as to the criminal law, does not necessarily bar private civil actions in tort or on some other grounds as a result of the facts alleged in the charge. For example, O. J. Simpson could be held civilly liable for wrongful death even after being tried and acquitted of murder. In federal states it also does not bar prosecution for the same offences under a statute at a different level of government. For example, in the United States someone acquitted of a state murder charge can be retried for the same actions on a federal charge of violating civil rights.