Apple's iOS system, used in iPhones, was second with a market share of 15 percent. Apple's new iPhone didn't come out until late in the quarter, while Samsung Electronics Co. and other Android makers had major releases earlier.
A year ago, Android had just 58 percent to the iPhone's 14 percent. Gains came largely at the expense of BlackBerry and Symbian phones, according to Thursday's report from IDC.
"Android has been one of the primary growth engines of the smartphone market since it was launched in 2008," said Ramon Llamas, a research manager for mobile phones at IDC. "In every year since then, Android has effectively outpaced the market and taken market share from the competition."
Google makes its operating system software available to phone makers to use in their devices for free. In doing so, Google wins prime placement for its online services, including search and maps. Apple does not license its iOS system to others.
All other mobile operating systems were in the single digits: BlackBerry at 4.3 percent, Symbian at 2.3 percent and Windows at 2 percent. Research In Motion Ltd. plans to start selling devices running a new version of BlackBerry early next year, while Microsoft launched a new version of its Windows phone software this week. Symbian is mostly used by Nokia Corp.
Companies making Android devices include Samsung, HTC Corp. and Motorola Mobility, which Google now owns.
Here are IDC's top operating systems based on worldwide smartphone unit sales and market share in the third quarter of 2012.
— Android (Google Inc.)—136 million units, 75 percent share (57.5 percent a year earlier)
— iOS (Apple Inc.'s iPhone)—26.9 million units, 14.9 percent share (13.8 percent a year earlier)
— BlackBerry (Research in Motion Ltd.)—7.7 million units, 4.3 percent share (9.5 percent a year earlier)
— Symbian (mostly used by Nokia Corp.)—4.1 million units, 2.3 percent share (14.6 percent a year earlier)
— Windows (Microsoft Corp.)—3.6 million units, 2 percent share (1.2 percent a year earlier)
— Linux—2.8 million units, 1.5 percent share (3.3 percent a year earlier)