Missouri Income Tax Withholding Payment and Filing Requirements
Employers in Missouri must conform with these state rules relating to filing income tax withholding returns.
Periodic Returns. Quarterly (Form MO-941) due the last day of the month following the end of the quarter; monthly (Form MO-941) due by the 15th of the following month; annually (Form MO-941) due by January 31 of the following year. Quarter-monthly (Form MO-941P) filing may be required.
Annual Returns. Form MO W-3 filed annually along with copies of all withholding statements and employee W-2 forms. The form is due on or before February 28 of the following year.