Tax Withholding

US Citizen Payroll Withholding

Employees must complete Federal Withholding Elections in GMS. All claims to allowances or exemptions from withholding are subject to review by the IRS. To make or change withholding elections in GMS, click on the 'Pay' icon, and under 'Action', select 'Withholding Elections'

W-4 (Federal)

  1. If applicable, check 'Last Name Differs from SS' (Social Security) and/or 'Nonresident Alien'
  2. Under 'Marital Status', click on the prompt button and select the appropriate status
  3. In the 'Number of Allowances' field, input the total number of allowances you are claiming. For instructions, see the W-4 worksheet. You may also use the online calculator provided by the IRS
  4. If you wish to have an additional amount withheld from each paycheck, input it in the 'Additional Amount' field
  5. Check 'Exempt' only if you meet both of the following conditions:
    • Last year I had a right to a refund of all federal income tax withheld because I had no tax liability
    • This year I expect a refund of all federal income tax withheld because I expect to have no tax liability
  6. When finished, click 'I Agree'
  7. Review your selections; when satisfied, click the submit button

You may also view these instructions in the GMS Onboarding manual.


State tax withholding forms must be filled out manually and sent directly to Payroll Services by fax to 202-687-9148. You may also hand deliver them to either of the following locations:

  • Darnall Hall, 2nd Floor, M-31
  • 2115 Wisconsin Avenue, 6th Floor, Suite 6110 

If you cannot find your state tax withholding form below, please contact Payroll Services for assistance.

Non-US Citizen Payroll Withholding

Non-US Citizen employees receiving compensation through Payroll Services must provide the following forms and documents to the Tax Department to request treaty benefits, exemption from FICA, or for determination of residency for tax status:

Non-US Citizen employees should contact the Tax Department with questions related to income tax withholding. Please direct all other income tax withholding questions to Payroll Services.