There are a lot of overseas stock market ISAs on offer. However, I am a little unsure about the tax advantages of these. Will try to explain why below. The UK has tax agreements with a lot of other countries, to prevent double taxation. For example, suppose a UK resident (resident for tax purposes) does a 2 month contract in the USA, the money they make might be liable to - say - Â£500 tax in the UK. However, if they have already paid Â£400 tax in the USA, all they pay to the UK Govt is Â£100 (Â£500, minus Â£400 already paid in USA). Suppose I opened a share ISA which invested in, say, the US stock market. Would any tax paid to the US authorities be recoverable? If not, and the only tax free element was any additional tax to be paid in the UK, such an ISA would appear to be less attractive to investors than a UK based one. Doesn't mean that you wouldn't invest abroad, just that the incentive is reduced. Alternatively, is the tax paid on any dividends (and also capital gains) recoverable from overseas governments? Grateful for any comments - and apologies if I have missed something really obvious.