Mississippi has no specific final paycheck deadline, so final pay generally comes on the next regular payday whether you quit or were fired.
Final paycheck deadline in Mississippi
What your final pay must include
Your final paycheck must include all the wages you earned through your last day. Whether it also has to include unused vacation depends on your state and your employer's policy, some states treat accrued vacation as wages that must be paid out. See Mississippi PTO payout rules. If an employer misses the deadline, many states add penalties. This is general information, not legal advice.