Cannabis Laws in Missouri

Current legal status

Missouri voters approved Amendment 3 in November 2022, which amended the state constitution to legalize adult-use cannabis for people 21 and older. The amendment took effect December 8, 2022, and licensed retail sales to adults began February 3, 2023 ^[1][2].

Medical cannabis was legalized earlier, in November 2018, through Amendment 2 ^[3]. Existing medical dispensaries were given a path to convert to "comprehensive" licenses that serve both medical patients and adult consumers.

Because both programs are written into the Missouri Constitution rather than passed as ordinary statutes, the legislature cannot repeal or substantially weaken them without another constitutional amendment approved by voters Strong evidence.

This article is informational and not legal advice. Cannabis laws change; verify current rules with the Missouri Division of Cannabis Regulation or a licensed Missouri attorney before relying on anything here.

Possession and personal use

Adults 21+ may possess up to 3 ounces of cannabis flower (or equivalent in other forms) without a medical card ^[1][2]. Registered medical patients may possess up to 6 ounces in a 30-day period ^[3].

Possession above 3 oz but under 6 oz by a non-patient is an infraction with a fine; larger amounts can still be charged as misdemeanors or felonies ^[1]. Public consumption remains illegal, as does consumption in a moving vehicle (open-container-style rules apply to cannabis). Driving while impaired by cannabis is prosecuted under Missouri's DWI statutes Strong evidence.

Cannabis remains federally illegal under the Controlled Substances Act, so federal land (national parks, military bases, post offices) and federally regulated activities (firearms purchases, certain federal jobs) are not covered by state legalization ^[4].

Home cultivation

Missouri allows home cultivation, but you must register with the Division of Cannabis Regulation and pay a fee (currently $100/year for adult-use consumers; medical patients pay a smaller fee) ^[2][5].

A registered individual may grow up to:

• 6 flowering plants
• 6 non-flowering plants (over 14 inches)
• 6 clones (under 14 inches)

Plants must be grown in a locked, enclosed space not visible from public view. Only the registered cultivator may access the plants. Two registered cultivators may share a household, doubling the plant count for that residence ^[2].

Unregistered home grow — even one plant — is still treated as illegal cultivation under Missouri law Strong evidence.

Retail, taxes, and the local-tax fight

Adult-use cannabis is sold through licensed dispensaries regulated by the Missouri Division of Cannabis Regulation (DCR). The state levies a 6% excise tax on adult-use sales (medical sales are taxed at 4%) ^[1][2].

Amendment 3 also allows local governments to add up to 3% in local sales tax, but only with voter approval ^[1]. This is where it gets contentious: many counties tried to stack their 3% tax on top of a city's 3% tax within incorporated areas. Dispensaries and the state argued only one local tax should apply inside city limits. In late 2024, the Missouri Supreme Court ruled in favor of stacking, allowing both city and county to charge their 3% in many cases ^[6] Strong evidence.

For consumers, this means total tax on adult-use cannabis in some Missouri jurisdictions can exceed 20% once state sales tax, the 6% excise, and stacked local taxes are added.

Medical program

Missouri's medical cannabis program remains active alongside adult-use. Patients get:

• Higher possession limits (6 oz / 30 days vs 3 oz)
• Lower tax rate (4% vs 6%)
• Lower home-cultivation registration fees
• Access at age 18 (with physician certification; minors require a parent/guardian as caregiver)

Qualifying conditions include cancer, epilepsy, glaucoma, intractable migraines, chronic medical conditions causing severe pain, PTSD, HIV/AIDS, and a physician-discretion category for any condition where a physician believes cannabis would help ^[3][5].

Cards are issued by the DCR and typically valid for up to three years ^[5].

Expungement

One of Amendment 3's most significant provisions: automatic expungement of most non-violent cannabis convictions for offenses now legal under the amendment ^[1][7]. Courts were directed to identify and expunge eligible misdemeanor records by June 8, 2023, and eligible felony records by December 8, 2023.

Progress has been uneven. As of 2024, hundreds of thousands of records had been expunged, but advocates and reporting outlets have documented significant backlogs in some counties ^[7] Strong evidence. People with prior cannabis convictions who believe they qualify but haven't seen action can petition the court directly.

What's still illegal

Even with legalization, the following remain prohibited in Missouri:

• Possession by anyone under 21 (non-patient)
• Public consumption (smoking, vaping, or eating in public spaces)
• Consumption in a motor vehicle, by driver or passenger
• Driving under the influence of cannabis
• Possession on K–12 school grounds, in correctional facilities, or on federal property
• Sale or transfer to a minor
• Selling without a license
• Crossing state lines with cannabis (federal offense)

Employers may still maintain drug-free workplace policies and test for cannabis, with limited protections for registered medical patients ^[2] Strong evidence. Landlords may prohibit smoking and home cultivation in rental properties.

Sources

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