The Miller test, also called the three-prong obscenity test, is the United States Supreme Court's test for determining whether speech or expression can be labeled obscene, in which case it is not protected by the First Amendment to the United States Constitution and can be prohibited.

Miller v. California, 413 U.S. 15 (1973), was a landmark decision of the US Supreme Court modifying its definition of obscenity from that of "utterly without socially redeeming value" to that which lacks "serious literary, artistic, political, or scientific value." It is now referred to as the three-prong standard or the Miller test.