Do foreigners have to pay inheritance tax in Thailand?

Yes, but with conditions:

• If a foreigner is a resident or domiciled in Thailand, they may be liable on Thai assets.
• If a non-resident foreigner inherits assets located in Thailand, they are taxed on those assets (not on assets outside Thailand).

However, foreign assets (outside Thailand) are generally outside the scope of Thai inheritance tax.

Also note peculiar rules for foreigners and land: while they may inherit land, in many cases they must sell it within a certain time or meet other restrictions