I know nothing about Belgium pensions but to use the UK as an example of where the Government pays a pension to (almost) everybody, there is a difference between a "Pension Paid by the Government" (E.g. the UK State Pension) and a "Pension Earned Whilst Working for the Government" (E.g. Public services, Military etc...) with the former being Tax Assessable if remitted to Thailand and the latter exempt. A quick look at the Belgium-Thailand DTA (https://www.rd.go.th/english/2558.html) suggests under Article 18 covers any pension earned whilst working for the Government wouldn't be taxable & Article 17 covers other Pensions (Private or State) which would be tax assessable... ARTICLE 17 Pensions 1. Subject to the provisions of Article 18, pensions or other remuneration for past employment arising in a Contracting State and paid to a resident of the other Contracting State may be taxed in the first - mentioned State. 2. Pensions or other remuneration for past employment shall be deemed to arise in a Contracting State if the payer is that State itself, a political subdivision or local authority or a resident of that State. Where, however, the person paying such income, whether he is a resident of a Contracting State or not, has in a Contracting State a permanent establishment, and such income is borne by the permanent establishment, then the income shall be deemed to arise in the Contracting State in which the permanent establishment is situated. ARTICLE 18 Government service 1. (a) Remuneration, other than a pension, paid by a Contracting State or a political subdivision or a local authority thereof to any individual in respect of services rendered to that state or subdivision or local authority thereof shall be taxable only in that State. (b) However, such remuneration shall be taxable only in the other Contracting State if the services are rendered in that State and the recipient is a resident of that State who: (1) is a national of that State; or (2) did not become a resident of that State solely for the purpose of performing the services. 2. (a) Any pension paid by, or out of funds created by, a Contracting State or a political subdivision or a local authority thereof to any individual in respect of services rendered to that State or subdivision or local authority thereof shall be taxable only in that State. (b) However, such pension shall be taxable only in the other Contracting State if the recipient is a national of and a resident of that State.