You can have Belgian nationality legally or voluntarily. You can also lose your Belgian nationality. More detailed information is available on the website of the Federal Government Department of Foreign Affairs
The Code of Belgian Nationality (WBN) contains the legal conditions relating to Belgian nationality and the Minister of Justice is the ‘guardian’ of Belgian nationality in general. The Nationality division of the Public Federal Service Justice monitors the appropriate application of the WBN.
If you are living in Belgium, contact your municipality for all general or personal questions about nationality. If you are living abroad, contact the competent Belgian embassy or consulate for all general or personal questions about nationality.