Cannabis in Oklahoma is legal for possession and use for medicinal purposes with a state-issued license, while CBD oil derived from industrial hemp is legal without a license.
As part of a larger trend nationwide to restrict cannabis, Oklahoma banned the drug in 1933. Through the decades, Oklahoma authorities actively prosecuted cannabis users, sellers and growers including through the use of helicopter patrols  
In 2014, Oklahomans for Health circulated a petition to get medical cannabis legalization on the ballot, but failed to gain sufficient signatures.
Meanwhile, in April, 2015, The Governor signed HB 2154 allowing the Sale of CBD oil with less than 0.3% THC under specified restrictions, however, the use of CBD oil manufactured from industrial hemp (which was sold over the counter, without restrictions) became widespread in Oklahoma during the mid-late 2010s. Later in 2015, Green the Vote announced that they were beginning a new petition drive to place medical legalization on the 2016 ballot. The initiative gathered the required number of signatures, but backers alleged that Attorney General Scott Pruitt had changed the verbiage of the initiative in a misleading way. After Oklahomans for Health sued over the ballot rewrite, the Oklahoma Supreme Court ordered the original language be restored. As result of the legal dispute, the vote for the initiative was pushed back to 2018. Governor Mary Fallin established a ballot date on January 4th 2018, of June 26th, 2018 as a referendum initiative.
The referendum (State Question 788) ultimately passed 57%-43%, making Oklahoma the 30th US state to legalize medical use of cannabis. This approval by popular vote was noteworthy as it happened during a primary election rather than in a general election.. SQ 788 instructed the state to promulgate a regulatory scheme for Marijuana online within 30 days and begin licensing by August 25. 2018, however, on July 10, 2018, the Oklahoma Board of Health voted 5-4 to ban smokable marijuana products at dispensaries and to require licensed pharmacists to be on-site at dispensaries. After 2 lawsuits were filed these regulations were dropped.  Some local jurisdictions have tried to further regulate licensed cannabis use but such efforts have largely failed under judicial review.
On August 1, 2018, many of the original rules promulgated by the Oklahoma Board of Health (OBH) were rescinded with the support of Oklahoma State Attorney general Mike Hunter who stated that the OBH rules overreached and did not meet the intent of SQ 788. Oklahoma City adopted the "simple possession" rule in their city code on October 26, 2018 and additionally lowered the maximum fine for possession of marijuana paraphernalia to $50.
Medical use regulations
The statewide regulator for marijuana is the Oklahoma Medical Marijuana Authority.
Under SQ 788, an individual who obtains a Medical Marijuana License from the state of Oklahoma may consume marijuana legally and may legally possess up to:
- 3 ounces of marijuana
- 6 mature marijuana plants (defined as plants that are in the budding stage)
- 6 seedling plants (defined as plants that are in the vegetative stage and are not yet budding)
- 1 ounce of concentrated marijuana
- 72 ounces of edible marijuana
- 8 ounces of marijuana in their residence
Smokable forms of medical marijuana can be legally consumed by license holders in any place that allows the smoking of tobacco products, while edible forms of medical marijuana can be consumed anywhere. All forms of medical marijuana are still deemed to be illegal under federal law; consequently Oklahoma medical marijuana license holders are not exempt from federal prosecution for cannabis possession when they are present on federal lands in Oklahoma (including military posts and lands administered by the National Park Service or the Department of Agriculture), as well as on tribal trust land.
CBD clinical trials
Prosecution for non-licensed use
Unlicensed simple possession of up to 1.5 ounces is now punishable by a misdemeanor conviction and a $400 fine.
Since October 1, 2013, DUI (driving under intoxication) penalties include being jailed for no less than 10 days or more than 1 year if: A person "has any amount of a Schedule I chemical or controlled substance, as defined in Section 2-204 of Title 63 of the Oklahoma Statutes, or one of its metabolites or analogs in the person’s blood, saliva, urine or any other bodily fluid at the time of a test of such person's blood, saliva, urine or any other bodily fluid administered within two (2) hours after the arrest of such person." A second offense will have longer sentencing as well as require an ignition interlock device that can only detect alcohol even if person is not a user of alcohol.
Feral hemp research
In 2018 Hempyre Genetics was hired to research strains of feral cannabis growing at undisclosed locations in Oklahoma, in order to advise legal hemp farmers as to what genetic traits were thriving in the state.
- Richard Davenport-Hines (10 November 2003). The Pursuit of Oblivion: A Global History of Narcotics. W.W. Norton. pp. 240–. ISBN 978-0-393-32545-4.
- "Oklahoma Narcotics Bureau Tackles Marijuana Operations From The Sky". Fort Smith/Fayetteville News - 5newsonline KFSM 5NEWS.
- In 1995, a Bureau of Indian Affairs anti-narcotics agent was killed when one of these helicopters crashed after striking power lines. "Oklahoma Heroes". google.com.
- CITE NEEDED
- "New medical marijuana petition filed for Oklahoma vote". Tulsa World.
- Bailey, Brianna (March 27, 2017). "Medical marijuana one step closer to Oklahoma ballot". NewsOK. Retrieved July 19, 2017.
- Shepherd, Todd (2017-02-20). "Pruitt confirmation adds another strong anti-marijuana voice to Trump cabinet". Washington Examiner. Retrieved 2017-03-11.
- NewsOn6.com. "Medical Marijuana Vote Set In Oklahoma".
- State Question (SQ) 788
- Cite Needed.
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- Philip Ross (30 April 2015). "Marijuana Legalization Oklahoma: Gov. Fallin Signs Bill Allowing Clinical Trials Of Medical Cannabis Derivative". International Business Times.
- "HB 1441" (PDF). The State of Oklahoma. 2013.
- "Your Oklahoma Pot Rights". Archived from the original on 2016-04-02.
- "Oklahoma life-for-hash bill signed, also includes life-for-brownies or grinders". NORML Foundation. 2011. Archived from the original on 2013-03-04. Retrieved 2016-11-15.
- firstname.lastname@example.org. "Bill Information". www.oklegislature.gov. Retrieved 2018-03-25.