The U.S. Embassy does not have a tax office available to provide tax advice, please see details below for available resources. On the Department of State’s website Travel.State.Gov, you can find out more about Federal Benefits and Obligations Abroad and visit the new FACTA FAQ page.
The Internal Revenue Service has a comprehensive website U.S. Citizens and Resident Aliens Abroad, which includes such information as When to File, Where to File, Taxpayer Identification Number, Exchange Rates, How to Get Tax Help, and Help with Unresolved Tax Problems. The IRS Office in Philadelphia provides international tax assistance and their contact info and hours are listed under the How to Get Tax Help section of this page. Tax Forms and Publications are also available under the References section of this page.
For a list of U.S. tax return preparers in Belgium, please visit the IRS webpage Directory of Federal Tax Return Preparers with Credentials and Select Qualifications and select Belgium as the country.
The U.S.-Belgium income tax treaty (PDF 82 KB) is in force since October 13, 1972. A technical explanation of this treaty (PDF 101 KB) can also be consulted.