I-502 was an initiative to the Washington State Legislature in 2012 that proposed the legalization of recreational marijuana use and sale to the general public within the borders of the State of Washington. The legislature adjourned without action in April 2012, automatically advancing the initiative to the general ballot the following November. The initiative passed 56 to 44 percent and certification for producers and growers began in December 2012.

I-502 restricts the sale of recreational marijuana products to individuals 21 years of age and older, taxing sales with revenue directed toward healthcare and substance-abuse prevention and education services. The law does not supersede federal law, therefore, it is illegal to transport or consume recreational cannabis outside the borders of Washington State.