More than two million iPads have been sold since the device was launched in the US on 3 April, Apple says.
The device's launch in nine countries outside the US on Friday appears to have pushed it past the milestone, although the company has not broken down the sales by geography.
Apple sold 300,000 in the US on 3 April, and passed the one million mark on 30 April. One month later, the total now stands at two million.
"Customers around the world are experiencing the magic of iPad, and seem to be loving it as much as we do," CEO Steve Jobs said in a statement.
"We appreciate their patience, and are working hard to build enough iPads for everyone."