A person generally commits the crime of prostitution by engaging in sexual contact or offering to engage in sexual contact in exchange for money or other consideration.

It is also a criminal offense to solicit (on a person's own behalf, or on behalf of another person), promote, or compel prostitution. For example, most states have laws that make it illegal to buy, sell, or profit from prostitution—which is generally the business of pimps and other human traffickers—known as pimping, pandering, procuring, soliciting, promoting, or compelling prostitution.

Prostitution laws vary from state to state and are generally located in a state’s statutes—often in the penal or criminal code.

In Montana (MT), prostitution is illegal under state law. According to Montana Code Annotated 2021, Section 45-5-601, a person commits the offense of prostitution if they engage in, agree to engage in, or offer to engage in sexual intercourse or any other sexual activity with another person in return for a fee, charge, or other compensation. This applies to both the person offering sexual services and the person receiving them. Additionally, the law in Montana criminalizes the acts of promoting prostitution (Section 45-5-603), which includes owning, controlling, managing, supervising, or otherwise keeping a house of prostitution or a prostitution business. It is also illegal to solicit for prostitution (Section 45-5-602), which means it is a crime to entice, induce, or procure another to engage in prostitution. Penalties for these offenses can range from fines to imprisonment, depending on the severity of the crime and whether it involves aggravating factors such as the involvement of minors.