The criminal offense of unlawful assembly generally means the assembly of multiple persons resulting in conduct that (1) is intended to commit a breach of the peace or other unlawful act; (2) creates an immediate danger of damage to property or injury to persons; (3) substantially obstructs law enforcement or other governmental functions or services; (4) is tumultuous or violent and likely to cause public alarm; or (5) deprives any person of a legal right or disturbs any person in the enjoyment of a legal right by using force or the threat of force.

Unlawful assembly laws vary from state to state and some states have related offenses such as rioting, riots and routs, participating in a riot, inciting a riot, failing to disperse, and disturbing the peace. The criminal offense of unlawful assembly may be included in the definition of one or more of these offenses or may be a separate criminal offense. These laws are generally located in a state’s statutes—often in the penal or criminal code.

In Texas, the concept of unlawful assembly is addressed under the Texas Penal Code. Specifically, the offense is often associated with 'Riot' as defined in Section 42.02 of the code. A person commits the offense of riot if he or she knowingly participates in an assembly of seven or more persons and during that assembly, there is conduct which creates an immediate danger of damage to property or injury to persons, substantially obstructs law enforcement or other governmental functions or services, or by force, threat of force, or physical action deprives any person of a legal right or disturbs any person in the enjoyment of a legal right. The offense of riot is considered a Class B misdemeanor. Texas law also includes related offenses such as 'Obstructing Highway or Other Passageway' (Section 42.03) and 'Disorderly Conduct' (Section 42.01), which can encompass behaviors that might be associated with unlawful assemblies. It is important for individuals to understand that participating in a protest or demonstration is legal, provided it does not cross into the territory of these offenses. An attorney can provide specific guidance on how these laws apply to particular situations.