I've just read (and adored) my son's copy of The Midnight Fox by Betsy Byars, who's American.
It came in a "classics" set that includes Ted Hughes and Marianne Storr, so obviously a proper serious level of classic. And it is definitely worthy of that company: utterly lovely book.
But because it was American, I'd known nothing of it - and having searched on here, just one poster has referred to it, ever. So I bet there are masses more books like that - ie, which are "classics" in their own country but just not well-known elsewhere.
So, if you grew up somewhere other than Britain - or had access to non-Brit-centric books as a child - what were your classics?