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

The Miller test was developed in the 1973 case Miller v. California. It has three parts:

• Whether the average person, applying contemporary community standards, would find that the work, taken as a whole, appeals to the prurient interest,
• Whether the work depicts/describes, in a patently offensive way, sexual conduct specifically defined by applicable state law,
• Whether the work, taken as a whole, lacks serious literary, artistic, political, or scientific value.

The third condition is also known as the SLAPS test. The work is considered obscene only if all three conditions are satisfied.

For legal scholars, several issues are important. One is that the test allows for community standards rather than a national standard. What offends the average person in Crawford, Texas may differ from what offends the average person in San Francisco. The relevant community, however, is not defined. Some critics of obscenity law, such as Jonathan Wallace and William Huston, argue that the existence of Miller proves that federal obscenity laws are in fact not defined, and thus unenforceable and legally dubious.

Another important issue is that Miller asks for an interpretation of what the "average" person finds offensive, rather than what the more sensitive persons in the community are offended by, as obscenity was defined by the previous test, the Hicklin test , stemming from the English precedent.

Because it allows for community standards and demands "serious" value, some worried that this test would make it easier to suppress speech and expression. They pointed out that it replaced a stricter test asking whether the speech or expression was "utterly without redeeming social value"--a much tougher standard than "serious" value. As used, however, the test generally makes it difficult to outlaw any form of expression. Even pornography, with the exception of child pornography, is argued to have some artistic or literary value.

In practice, pornography showing genitalia and sexual acts is not normally obscene according to the Miller test. For instance, in 2000 a jury took only a few minutes to clear Larry Peterman, Movie Buffs video store owner in Provo, Utah, which had often boasted of being one of the most conservative counties in the US. Researchers had shown that guests at the local Marriott hotel were disproportionately large consumers of pay-per-view pornographic material, obtaining far more material that way than the store was distributing [1][2].

The advent of the Internet has made this definition more difficult to maintain; as material published on a web server in one place can be read by a person residing anywhere else where there is a computer with internet access, there is a question as to which jurisdiction should apply. The pending case United States of America v. Extreme Associates includes some content delivered purely over the Internet and may clarify the situation. This case includes a video called Forced Entry, which includes depictions of rape, murder, suffocation, beatings and urination in sexual contexts. Each of the components when considered alone, is not uncommon in sexual fantasy (murder probably being the least common) and, except for murder, feature routinely in sexual activities of varying proportions of the US population. Since part of the Miller purpose was to consider the effect on the members of the community who would see the material for sale on the street it's unclear how material which goes directly from a vendor to a residence and is never seen by the community will be judged.