It is easy for landlords and tenants to end a month-to-month tenancy in Missouri. (The situation is more complicated when it comes to breaking a fixed-term lease.)
In Missouri, landlords are not required to give tenants a reason why they are terminating a month-to-month tenancy. Note, though, that it is illegal for a landlord to end a month-to-month tenancy because of a discriminatory motive—in other words, a reason that is based on the tenant's race, color, religion, national origin, sex, familial status, or disability.
Missouri law requires landlords to give the tenant a written termination notice stating that the tenancy will end on a rent-paying date (a date that rent would be due if the tenancy were to continue) not less than one month after receipt of the notice. If the rental agreement states that the landlord will give more notice, the landlord must abide by the terms of the rental agreement.
Landlords can legally provide less notice in certain circumstances—for example, when a tenant has not paid rent, has violated other terms of the rental agreement (for example, bringing in an unauthorized tenant), or has violated basic responsibilities imposed by law (such as by dealing drugs on the rental property).
It is equally easy for tenants in Missouri to get out of a month-to-month rental agreement. Missouri law requires tenants to give the landlord a written termination notice stating that the tenant will be ending the tenancy on a rent-paying date (a date that rent would be due if the tenancy were to continue) not less than one month after receipt of the notice. If the rental agreement states that the tenant will give more notice, though, the tenant must abide by the terms of the rental agreement.
In some situations, tenants might able to move out with less (or no) notice—for example, when a landlord seriously violates the rental agreement or fails to fulfill legal responsibilities affecting the tenant's health or safety.
Check Missouri state law (Mo. Rev. Stat. § 441.060) for the exact rules and procedures for how landlords must prepare and serve termination notices and for any special rules regarding how tenants must provide notice. See the Laws and Legal Research section of Nolo for more advice on finding and reading statutes and court decisions.
The Missouri Attorney General's guide to landlord-tenant law also has useful information on Missouri landlord-tenant laws and how month-to-month tenancies end.