Burden of proof refers to the amount of evidence or proof required to adequately prove disputed facts in a court of law, and which party has the obligation to prove the disputed facts in order to prevail in court. In criminal prosecutions (cases) the government or prosecution has the burden to prove the accused defendant’s guilt beyond a reasonable doubt. This has been the standard for criminal prosecutions in the United States since at least 1880 when it was first mentioned by the U.S. Supreme Court. The determination of whether there is reasonable doubt as to an accused defendant’s guilt may be characterized by the question of whether there is an alternative explanation of the facts that seems plausible to the jurors.

In Oklahoma, as in all states across the United States, the burden of proof in criminal prosecutions lies with the government or prosecution. This means that the prosecution must prove the defendant's guilt 'beyond a reasonable doubt,' which is the highest standard of proof required in the American legal system. This standard has been a cornerstone of criminal law since it was articulated by the U.S. Supreme Court in the 1880s. It ensures that a defendant is presumed innocent until proven guilty, and it requires the jury to be convinced to a high degree of certainty that the defendant committed the crime. If there is a plausible alternative explanation of the facts that could lead to a reasonable doubt in the minds of the jurors, then the jury is obliged to acquit the defendant. This principle is a fundamental aspect of criminal justice in Oklahoma and provides a critical safeguard against wrongful convictions.