Missouri's law regarding wage payment can be located in Title XVIII, Chapter 290 of the Missouri Revised Statutues, and other sections mentioned below.

Employees paid semimonthly, exception--statement of deductions --violation, misdemeanor.
290.080.

All corporations doing business in this state, and all persons operating railroads or railroad shops in this state, shall pay the wages and salaries of their employees as often as semimonthly, within sixteen days of the close of each payroll period; provided, however, that executive, administrative and professional employees, and sales people and other employees compensated in whole or in part on a commission basis, at the option of such employers, may be paid their salaries or commissions monthly. Such corporations and persons either as a part of the check, draft or other voucher paying the wages or separately, shall furnish the employee at least once a month a statement showing the total amount of deductions for the period. Any corporation or person violating this section shall be deemed guilty of a misdemeanor, and upon conviction thereof shall be fined in any sum not less than fifty dollars, nor more than five hundred dollars, for each offense.

Factory employees paid semimonthly--amount withheld--penalty.
290.090.

The employees of the operators of all manufactories, including plate glass manufactories, operated within this state shall be regularly paid in full of all wages due them at least once in every fifteen days, in lawful money, and at no pay day shall there be withheld from the earnings of any employee any sum to exceed the amount due him for his labor for five days next preceding any such pay day. Any such operator who fails and refuses to pay his employees, their agents, assigns or anyone duly authorized to collect such wages, as in this section provided, shall become immediately liable to any such employee, his agents or assigns for an amount double the sum due such employee at the time of such failure to pay the wages due, to be recovered by civil action in any court of competent jurisdiction within this state, and no employee, within the meaning of this section, shall be deemed to have waived any right accruing to him under this section by any contract he may make contrary to the provisions hereof.

Thirty days' notice of reduction of wages, how.
290.100.

Any railway, mining, express, telegraph, manufacturing or other company or corporation doing business in this state, and desiring to reduce the wages of its employees, or any of them, shall give to the employees to be affected thereby thirty days' notice thereof. Such notice may be given by posting a written or printed handbill, specifying the class of employees whose wages are to be reduced and the amount of the reduction, in a conspicuous place in or about the shops, station, office, depot or other place where said employees may be at work, or by mailing each employee a copy of said notice or handbill, and such company or corporation violating any of the provisions of this section shall forfeit and pay each party affected thereby the sum of fifty dollars, to be recovered by civil action in the name of the injured party, with costs, before any court of competent jurisdiction.

Payment due discharged employee--exceptions--penalty for delay.
290.110.

Whenever any person, firm or corporation doing business in this state shall discharge, with or without cause, or refuse to further employ any servant or employee thereof, the unpaid wages of the servant or employee then earned at the contract rate, without abatement or deduction, shall be and become due and payable on the day of the discharge or refusal to longer employ and the servant or employee may request in writing of his foreman or the keeper of his time to have the money due him, or a valid check therefor, sent to any station or office where a regular agent is kept; and if the money or a valid check therefor, does not reach the station or office within seven days from the date it is so requested, then as a penalty for such nonpayment the wages of the servant or employee shall continue from the date of the discharge or refusal to further employ, at the same rate until paid; provided, such wages shall not continue more than sixty days. This section shall not apply in the case of an employee whose remuneration for work is based primarily on commissions and whose duties include collection of accounts, care of a stock or merchandise and similar activities and where an audit is necessary or customary in order to determine the net amount due.

Action by employees for breach of employment contract.
290.130.

Any such servant or employee whose employment is for a definite period of time, and who is discharged without cause before the expiration of such time, may, in addition to the penalty prescribed by this law, have an action against any such employer for any damages he may have sustained by reason of such wrongful discharge, and such action may be joined with an action for unpaid wages and penalty.

Deductions authorized to be made from state employees' compensation --debts owed to state, child support payments, tuition programs, --cafeteria plan, requirements.
33.103.

1. Whenever the employees of any state department, division or agency establish any voluntary retirement plan, or participate in any group hospital service plan, group life insurance plan, medical service plan or other such plan, or if they are members of an employee collective bargaining organization, or if they participate in a group plan for uniform rental, the commissioner of administration may deduct from such employees' compensation warrants the amount necessary for each employee's participation in the plan or collective bargaining dues, provided that such dues deductions shall be made only from those individuals agreeing to such deductions. Before such deductions are made, the person in charge of the department, division or agency shall file with the commissioner of administration an authorization showing the names of participating employees, the amount to be deducted from each such employee's compensation, and the agent authorized to receive the deducted amounts. The amount deducted shall be paid to the authorized agent in the amount of the total deductions by a warrant issued as provided by law.

2. The commissioner of administration may, in the same manner, deduct from any state employee's compensation warrant:

(1) Any amount authorized by the employee for the purchase of shares in a state employees' credit union in Missouri;

(2) Any amount authorized by the employee for contribution to a fund resulting from a united, joint community-wide solicitation or to a fund resulting from a nationwide solicitation by charities rendering services or otherwise fulfilling charitable purposes if the fund is administered in a manner requiring public accountability and public participation in policy decisions;

(3) Any amount authorized by the employee for the payment of dues in an employee association;

(4) Any amount determined to be owed by the employee to the state in accordance with guidelines established by the commissioner of administration which shall include notice to the employee and an appeal process;

(5) Any amount voluntarily assigned by the employee for payment of child support obligations determined pursuant to chapter 452 or 454, RSMo; and

(6) Any amount authorized by the employee for contributions to any "qualified state tuition program" pursuant to Section 529 of the Internal Revenue Code of 1986, as amended, sponsored by the state of Missouri.

3. The commissioner of administration may establish a cafeteria plan in accordance with Section 125 of Title 26 United States Code for state employees. The commissioner of administration must file a written plan document to be filed in accordance with chapter 536, RSMo. Employees must be furnished with a summary plan description one hundred twenty days prior to the effective date of the plan. In connection with such plans, the commissioner may:

(1) Include as an option in the plan any employee benefit, otherwise available to state employees, administered by a statutorily created retirement system;

(2) Provide and administer, or select companies on the basis of competitive bids or proposals to provide or administer, any group insurance, or other plan which may be included as part of a cafeteria plan, provided such plan is not duplicative of any other plan, otherwise available to state employees, administered by a statutorily created retirement system; and

(3) Reduce each participating employee's compensation warrant by the amount necessary for each employee's participation in the cafeteria plan, provided that such salary reduction shall be made only with respect to those individuals agreeing to such reduction. No such reduction in salary for the purpose of participation in a cafeteria plan shall have the effect of reducing the compensation amount used in calculating the state employee's retirement benefit under a statutorily created retirement system or reducing the compensation amount used in calculating the state employee's compensation or wages for purposes of any workers' compensation claim governed by chapter 287, RSMo.

4. Employees may authorize deductions as provided in this section in writing or by electronic enrollment.