Xiaomi is now the fourth-biggest smartphone seller

A man walks past a Xiaomi logo displayed outside the company's headquarters in Beijing on Friday, Sept. 12, 2014.
Brent Lewin | Bloomberg | Getty Images
A man walks past a Xiaomi logo displayed outside the company's headquarters in Beijing on Friday, Sept. 12, 2014.

Watch out Apple and Samsung, the Chinese company Xiaomi is creeping up in the ranks of smartphone-makers.

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The company is now the fourth-biggest seller of smartphones worldwide, right behind Huawei, according to Gartner.

Xiaomi sold 15.8 million units in the third quarter of this year, a 322 percent increase from the same period a year ago, when Gartner reported it sold 3.6 million units.

Xiaomi isn't the only Chinese smartphone-maker that saw growth in sales year over year.

Three of the top five smartphone-makers worldwide are Chinese companies including Huawei, Xiaomi and Lenovo. Collectively, these three companies accounted for about 15 percent of all smartphone sales in the third quarter.

The other two leading handset companies were Samsung, which sold 73.2 million units, and Apple, which sold 38.2 million smartphones.

Read More China's Xiaomi makes strides in smartphone race

Apple's iPhones sales grew 26 percent from a year ago, while Samsung's sales dropped 10.8 percent, according to Gartner.

In China alone, which is Samsung's biggest market, its sales fell 28.6 percent.

Worldwide smartphone sales by vendor in 3Q 2014 (thousands of units)

Company 3Q14 3Q13
Samsung 73,212.40 80,356.80
Apple 38,186.60 30,330.00
Huawei 15,934.90 11,665.70
Xiaomi 15,772.50 3,617.50
Lenovo 15,011.90 12,882.00
Others 142,891.60 111,445.00
Source: Gartner