According to the research firm, over 281.6 million units of smartphones were shipped worldwide in the first quarter of 2015.
"This growth was led by strong smartphone sales in emerging markets (excluding China); the fastest growing regions were emerging Asia/Pacific, Eastern Europe, and the Middle-East and North Africa," Gartner said in a statement.
Due to these high-performing regions, the emerging markets achieved a 40 percent increase in sales during the quarter.
In terms of overall mobile phone market (smartphone and feature phone), sales grew 2.5 percent to 460.2 million units in the reported quarter from 448.9 million units in March 2015 quarter.
Samsung led the market with 21.3 percent share, followed by Apple (13.1 percent), Microsoft (7.2 percent), LG Electronics (4.3 percent) and Lenovo (4.2 percent).
During the said quarter, local brands and Chinese vendors came out as the key winners (in smartphones) in emerging markets, Gartner Research Director Anshul Gupta said.
"These vendors recorded an average growth of 73 percent in smartphone sales and saw their combined share go up from 38 percent to 47 percent during the first quarter of 2015," Gupta added.
Samsung continued to see a decline in sales and share during the first quarter of 2015 at 24.2 percent (81.1 million units) from 30.4 percent share (85.5 million units) of smartphone sales in the year-ago period.
"We expect Samsung's drop rate to be slower than that seen in recent quarters with sales of its new S6 smartphones starting in the second quarter of 2015, and its Galaxy Alpha receiving good response," he said.
Apple continued to exhibit a strong performance in the quarter, particularly in China. iPhone sales were up 72.5 percent (60.17 million units) during the first quarter of 2015.
"Apple's extension into more Asian markets helped it close the gap with Samsung globally," Gupta said.
Lenovo, Huawei and LG Electronics followed in the smartphone tally with 5.6 percent, 5.4 percent and 4.6 percent share, respectively in the reported quarter.
In terms of operating system, Android's share fell by 1.9 percentage points to 78.9 percent, while iOS (Apple) grew year-on-year (to 17.9 percent) for the third consecutive quarter.
"The performance of Windows Phone (2.5 percent share) remained flat, mainly due to a weak ecosystem and a less desirable mobile brand, together with a strong and established competitive smartphone market," Gupta said.
The upcoming Windows 10 will create a consistent user experience across all devices, but it remains to be seen whether developers will follow, he added.
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