The iPhone continues its rampant growth as it expands overseas, with particular strength in China and the rest of Asia. Nokia slips two places to third, behind Samsung.
Apple, followed closely by Samsung Electronics, overtook Nokia in global smartphone market share during the second quarter.
Apple controlled nearly a fifth of the smartphone market, or a share of 18.5 percent, as it shipped more than 20 million iPhones, according to market research firm Strategy Analytics. Samsung Electronics wasn't far behind, with 17.5 percent of the market share and 19.2 million smartphones shipped. Nokia fell to third, with its market share plunging by more than half to 15.2 percent from 38.1 percent a year ago.
The ever-shifting top of the smartphone food chain is illustrative of the ultra-competitive nature of the business. Over the past year, Nokia has seen its market share drop as consumers opted for more sophisticated operating systems made by Apple and Google. The declines have forced Nokia to partner with Microsoft and switch to its Windows Phone operating system.
Apple's success continues to hinge on the smash hit iPhone. The company's momentum is expected to only keep building, with the next version expected to come out in September.
• iPhone 5 rumor roundup
• iPhone doubles world market share, outpaces rivals
• Samsung profit slides, but smartphones strong • 8 great tips for iOS 5
Another ingredient for its success: healthy expansion into international markets, with Strategy Analytics pointing to China and the rest of Asia as particular sources of strength.
Samsung, meanwhile, has enjoyed broad adoption of its Galaxy S smartphone franchise. Rather than position it as a "hero phone" at a single carrier, the company has opted to sell the device to as many carriers as possible, making its rapid ascension possible.
Samsung earlier reported a decline in its second-quarter profit, but said smartphone sales continued to grow. Yesterday, the company said it had sold 5 million units of the Galaxy S II in the first 85 days it was on store shelves. Samsung's rapid improvement have some wondering when it may overtake Apple for the smartphone business.
Overall, the global smartphone market grew by 76 percent to 110 million units shipped.
Separately, IDC reported that Apple more than doubled its market share for all mobile phones to 5.6 percent in the second quarter, signaling the largest jump for any of the handset vendors. Based on total handsets, Apple remained in fourth place. Nokia remained the top handset maker despite its market share falling to 24.2 percent from 33.8 percent a year ago, as its strength in low-end handsets in emerging markets has kept its pole position secure.
Samsung, which also has a large business selling basic handsets to markets around the world, had the second-largest market share. Its share slipped slightly as more people moved away from those basic handsets.