[1] The result was the Belgian nationality code, which was legislated on 28 June 1984 and largely took effect on 1 January 1985.

In 2002, Belgium denounced the Strasbourg Convention, which opened up the path to allowing for multiple nationality following naturalisation.

In 2008, the country removed its last remaining provisions that prevented the acquisition of multiple nationalities.

Where a person is required to make a declaration (déclaration / verklaring), this must usually be made at the municipality or diplomatic mission where they are registered.

Anyone listed in the National Register has the right to inspect their record[5] and request for it to be corrected if it is inaccurate.

A person born in Belgium to foreign parents is attributed Belgian nationality if the person: Effectively these clauses result in Belgian nationality being attributed to the children of long-resident immigrants and the grandchildren of immigrants.

[12] The distinction is that declaration is a legal right, based on meeting the conditions, whereas naturalisation is a privilege that the government can decide whether or not to accord.

Declaration is now the principal route through which foreigners can acquire Belgian nationality, and naturalisation has become extremely rare.

The most common countries of origin have historically been Morocco, Romania, Poland, the United Kingdom and Italy.

[14] Belgian nationality can be lost through renunciation, deprivation, residence overseas (satisfying specific criteria) or in certain cases applying to children.

From 9 June 2007 to 28 April 2008, this only applied in respect of voluntarily obtaining the nationality of a country that was still a signatory to the 1963 Strasbourg Convention on Multiple Nationality (i.e. Austria, Denmark, France, Ireland, Italy, Luxembourg, the Netherlands, Norway, Spain or the United Kingdom).

A person who has lost their Belgian nationality (other than by deprivation) may recover it by making a recovery declaration (déclaration de recouvrement / verklaring tot herkrijgen).

This rarely-publicised and extremely rarely-exercised right is provided for under Article 10 of the Loi sur l'accès au territoire, le séjour, l'établissement et l'éloignement des étrangers of 15 December 1980.

A person who lost their Belgian nationality following residence overseas (as per the criteria described above under "Loss of Belgian nationality") must normally return to Belgium and reside in Belgium for 12 months before making a recovery declaration.

The Crown Prosecutor has some latitude to approve or decline such applications (from a person resident abroad) based on the description/reasons provided.

A person seeking to make a declaration to acquire or recover Belgian nationality must satisfy various requirements and follow a standard procedure, as follows: The person is required to have had their main residence in Belgium for the prescribed period on a legal and uninterrupted basis.

The person is also required, as at the time of the declaration, to hold the right to continue residing in Belgium indefinitely.

The prosecutor will check that the person satisfies the criteria, as well as whether there are any serious negative facts (faits personnels graves / gewichtige feiten eigen) that would preclude the person from being accorded Belgian nationality (such as a criminal record or terrorist links).

The names of new citizens are periodically published in the Belgian official journal (Moniteur belge / Belgisch Staatsblad).

Citizens living in Belgium are required to register with their local municipality, through which they gain access to a variety of government services.

Citizens living abroad have the option, but not the obligation, to register with their local Belgian embassy or consulate, through which they can request some of the same services, such as renewing an identity card or passport.

In 2020, Belgium was accorded a UN Human Development Index (HDI) score of 0.931, ranking the country 14th for quality of life.

Belgian citizens thus enjoy the right of free movement to live and work in any country within the EU/EEA/Switzerland, as granted in Article 21 of the EU Treaty.