Missouri does not tax non-resident remote workers who work from outside the state.
Missouri Statute Section 143.181 (2)(2) states that the Missouri-source income of a non-resident is income from "a business, trade, profession, or occupation carried on in this state."
https://law.justia.com/codes/missouri/2011/titlex/chapter143/section143181/
Therefore the income of a KS resident working remotely in KS for a MO employer is not taxable by MO. Conversely, the income earned by a MO non-resident from work actually performed in MO is entirely taxable by MO.
A MO non-resident who works both within and without MO during the tax year would apportion his income accordingly.
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
