A woman walks past a signboard of Samsung Galaxy S3 at a mobile phone shop in Seoul. (AFP Photo/Jung Yeon-Je)
Strategy Analytics estimated Samsung sold 18
million S3 models in the third quarter, compared with iPhone 4S sales of 16.2 million.
Strong sales of the flagship Galaxy S3 - which comes with a large 4.8 inch touchscreen - helped Samsung post a record $7.3 billion operating profit in the July-September quarter.
"Samsung's Galaxy S3 has proven wildly popular with consumers and operators across North America, Europe and Asia," said analyst Neil Mawston, adding the new iPhone 5 would likely reclaim the top spot for Apple in the current quarter.