Public indecency is a legal term regarding acts or behaviors that may or may not be illegal, but are considered private behavior that could harm the public in some fashion. Typically, actions covered under public indecency laws are sexual in nature, ranging from public nudity to solicitation for prostitution. These laws tend to change as moral and ethical societal norms shift over time.

Not surprisingly, many behaviors that were once considered public indecency are no longer widely considered to be so; in the early 20th century, women could be arrested or fined for wearing bathing suits that exposed their arms or knees. Although standards have relaxed over time, the aim of public indecency laws remains the same; they are generally meant to prevent unwanted public exposure to behaviors that might be found offensive.

Some criminal offenses covered under public indecency laws include being nude or partially nude in public areas, engaging in sexual activities such as masturbation or intercourse in a public location, or exposing minors to sexually explicit images or behavior. Solicitation for prostitution may carry an indecency charge along with criminal charges for soliciting and engaging in prostitution where it is illegal. Interestingly, some regions also include activities such as adultery and homosexual behavior under public indecency laws, even if these behaviors are conducted in private.

Although in many areas the restrictions on decency laws have waned, there are still some controversies about the right to determine and enforce these laws, as well as the classifications of certain behaviors as criminal. In California, for example, women can be charged with public indecency and required to register as a sex offender for sunbathing topless, whereas for men, toplessness is not considered a crime. Laws such as this form a basis for a legal and ethical argument that public indecency statutes can be used to impose sexism and selective attitudes toward morality and equality.

The scope of public indecency laws depends largely on the structure of the laws governing behavior in the region. In some areas, prostitution and nude bathing are legal, where as in neighboring regions, they are criminal offenses. More liberal areas may have few public restrictions on clothing as long as genitalia are covered, but some regions have decency laws insisting on certain dress codes and can fiercely penalize offenders with jail time, fines, whipping, and other serious punishments.