Mo. Rev. Stat. § 143.174
For all tax years beginning on or after January 1, 2016, for purposes of calculating the Missouri taxable income as required under section 143.011, one hundred percent of the income received by any person as salary or compensation in any form as a member of the active duty component of the Armed Forces of the United States, and to the extent that such income is included in the federal adjusted gross income, may be deducted from the taxpayer's Missouri adjusted gross income to determine such taxpayer's Missouri taxable income. If such person files a combined return with a spouse, any military income received while engaging in the performance of active duty may be deducted from their Missouri combined adjusted gross income. For the purposes of this section, "salary or compensation" shall include any signing bonus.
§ 143.174, RSMo