The Italians are quite clever in that they have been able to pretty much brand themselves as being one of the best producers of olive oil, but all is not quite as it seems.
Instead, it turns out that while Italy does indeed produce some olive oil, that they are bending the laws and rules somewhat and providing us with a bit of a con. Rather than producing it all on their own, they are also the biggest importers of olive oil with the majority of it coming from Spain. Upon its arrival in Italy, they then simply rebrand it as Italian and sell it once again.
This accounts for the biggest percentage of the olive oil that is sold as being from the country, and there will often be no sign that this is indeed the case. So, the next time you see something as being branded from that country, then unless you have a cast-iron guarantee that this is the case, then perhaps taking it with a pinch of salt would be the best way forward.