The iPhone 4S has been dethroned by the Samsung Galaxy S III as the best-selling smartphone in the world according to a new report from Strategy Analytics.

The Galaxy S III shipped 18 million units in the third quarter compared to the iPhone 4S shipping just 16.2 million, likely affected by the launch of the iPhone 5, which sold six million units in the quarter.

Smartphone Marketshare, Samsung Galaxy S III sales figures, Apple iPhone sales

As for market share, the Galaxy S III now holds a 10.7% share of the global smartphone market compared to the iPhone 4S’ 9.7%. Samsung’s efforts to hold the top smartphone spot aren’t slowing down, either, as the company announced it has sold more than 30 million units this year, 10 million of which came in the last two months.

“We expect the new iPhone 5 to out-ship Samsung’s Galaxy S3 in the coming fourth quarter of 2012 and Apple should soon reclaim the title of the world’s most popular smartphone model,” said Neil Mawston, Executive Director at Strategy Analytics.

With the release of Microsoft‘s Windows Phone 8 devices, competition in the smartphone world is heating up, and it will be interesting to see how the market changes over the next year.