Affirmation, a mode of solemn verification permitted by the law, in the place of an oath, to persons who are unwilling from conscientious motives to be sworn. This departure from the usual rule of exacting an oath was first introduced into the English law in favor of Quakers; but by the present law there, and ever since 17 and 18 Victoria, ch. 125 (1854), any person called as a witness or desiring to make an affidavit or deposition, who will solemnly declare that the taking of an oath is, according to his religious belief, unlawful, may affirm or declare to the truth of his statement; and the statute requires that the officer taking the affirmation shall recite in his certificate that the affirmant declared that an oath was unlawful according to his religious belief. By the statute of 24 and 25 Victoria, ch. 66 (1861), all persons refusing to be sworn in criminal proceedings may make their solemn affirmation instead. In the United States an affirmation, even without the suggestion of any reason for preferring it, is probably everywhere received in place of an oath.

The legal effect of both is the same, and perjury is committed by affirming as well as by swearing falsely, wilfully, and corruptly.