As a rule, Belgium does not grant any relief for double taxation, except for the inheritance tax paid abroad in respect to real property in another country. Only this inheritance tax can be offset against the inheritance tax due in Belgium. Any other capital taxes paid abroad can only be set-off against the net value of the assets as a liability of the estate.

In practice, this means that, even if there is no inheritance tax between spouses in e.g. the United Kingdom, they will have to declare the British property in the Belgian inheritance tax return, and pay Belgian inheritance tax on the British property. They can offset the British inheritance tax, but since that is nil, that they would have paid.

The double taxation treaties which Belgium has signed with most European countries, relate only to income tax and not to inheritance tax. Belgium has signed two double taxation treaties relating to inheritance tax, with France and Sweden.