Android captured 27 percent share, with Microsoft lagging behind at 2 percent and Research In Motion's (RIM) QNX OS at 1 percent.

The sell-in statistics do not include e-book readers.

Android's share rose to 27 percent from a meager 2 percent during the year-ago quarter on shipments that rose to 4.5 million from a year-ago 100,000, and Android's share is poised to go higher with the launch of Amazon's Kindle Fire, Strategy Analytics said.

"Dozens of Android models distributed across multiple countries by numerous brands such as Samsung, Acer and others have been driving volumes," said Neil Mawston, director at Strategy Analytics. "Industry eyes will next turn to the commercial launch of the Amazon Fire. Amazon's strategy of minimizing its hardware price is set to ignite the entry-level tablet segment and attract more mass-market consumers."

The study also claimed that "the future release of Windows 8 cannot come quickly enough for Microsoft, so its hardware partners can start competing more effectively in the tablet space." As for RIM's QNX platform, the study said, "The next-generation PlayBook 2.0 model will need to offer a much improved ecosystem for messaging and consumer apps if it wants to take off."