Windows Phone 7 Will Overtake iOS by 2015, Says Gartner

By 2012, nearly 50 percent of the global smartphone market will run Google’s Android OS, which by then will be the world’s most popular mobile operating system, according to Gartner. Apple’s iOS will be the second most popular with 18.9 percent share. And with a 12.6 percent share, Research In Motion’s BlackBerry will be the third.

But by 2015, those market rankings will have changed quite a bit, with an entirely new OS leapfrogging its rivals for the number two spot: Microsoft’s Windows Phone 7.

Gartner says that Microsoft’s new alliance with Nokia will drive WinPho 7 from a 10.8 percent market share in 2012 to 19.5 percent market share in 2015, roughly equivalent to the share Nokia’s Symbian OS holds today.

iOS by that time will have fallen to third place with a 17.2 percent share, and RIM’s BlackBerry OS to third with an 11.1 percent share. That’s an impressive gain for Microsoft, but a bit of a disappointment for Nokia which essentially ends up treading water. Said Gartner, “though this is an honorable performance it is considerably less than what Symbian had achieved in the past underlying the upward battle that Nokia has to face.”

Oh, for the record, Gartner was saying something entirely different just six months ago. So take this latest attempt to slap a four-year forecast on a landscape that changes as quickly as the smartphone market’s does with a grain of salt.

UPDATE: Great analysis of all this over at Asymco.