The fastest growing regions were emerging Asia/Pacific, Eastern Europe, and the Middle East and North Africa, according to the Gartner report.
Strong smartphone sales in emerging markets -- excluding China -- helped drive the smartphone market to sales of 336 million units, an increase of 19.3 per cent during the first quarter of 2015, according to a report from IT research firm Gartner.
The fastest growing regions were emerging Asia/Pacific, Eastern Europe, and the Middle East and North Africa, according to the report.
A similar report released by IDC projected smartphone shipments would grow 11.3 percent in 2015, down from 27.6 percent in 2014, but on track with IDC's previous smartphone forecast of 11.8 percent growth in 2015.
The IDC report noted it expects this to be the first year in which China's smartphone growth, forecast to be 2.5 percent in 2015, will be slower than the worldwide market.
Related to the China forecast, Android smartphone growth, at 8.5 percent, is also expected to be slower than the worldwide market in 2015.
Gartner found iPhone sales were up 72.5 percent in China during the first quarter of 2015, making Apple the top smartphone vendor in the country--just ahead of Xiaomi--for the first time.
Greater China also became Apple's largest volume market, ahead of North America, thanks to strong sales in China during the first quarter of 2015.
Amongst the top five global smartphone vendors, Samsung continued to see a decline in sales and share during the first quarter of 2015, sliding from a 30 percent market share in the first quarter of 2014 to 24.2 percent in the first quarter of 2015.
Apple saw a slight uptick in market share, climbing to 17.9 percent from 15.3 percent compared to the same period last year.
The IDC report said it expects iOS smartphones to grow 23 percent in 2015 and remain above worldwide market growth rates throughout the forecast.
The report also noted that while overall smartphone growth will continue to slow, many markets are expected to experience robust growth in 2015 and beyond, and worldwide shipment volumes are forecast to reach 1.9 billion units annually by 2019.
Back to the Gartner report, in the smartphone operating system (OS) market, Android's share fell by 1.9 percentage points, while iOS grew year-on-year for the third consecutive quarter, and Windows landed far back in third place with just 2.5 percent market share.
Overall, the report found worldwide mobile phone sales to end users totaled 460.3 million units during the first quarter of 2015, a 2.5 percent increase from the same period in 2014, with Samsung, Apple, Microsoft, LG Electronics and Lenovo ranked as the top five leading original device manufacturers (OEMs).