35 Miss. Code R. § 3-11-08-100
An employee from whose wages tax is withheld should claim credit for the tax withheld on his income tax return for the calendar year during which the tax was withheld. Credit will be allowed only if a proper copy of his withholding statement, Form W-2, or other authorized wage and tax statement, is attached to his return. A fiscal-year taxpayer should claim credit for the tax withheld on his return for his fiscal year beginning in the calendar year during which the tax was withheld. For example, a taxpayer having a fiscal year ending July 31 is entitled to credit for tax withheld during the calendar year 1986 on his return for his fiscal year ending July 31, 1987. If more than one tax year begins during the calendar year during which the tax was withheld, the credit should be claimed on the return for the last such taxable year.
35 Miss. Code. R. § 3-11-08-100