Android tablet shipments have been running higher than Apple iPad shipments all year.
But Apple, thanks to higher priced units, has remained the leader in revenue until this latest quarter.
"For the first time Android devices accounted for a greater share of the market in revenue terms than iOS," Morgan Stanley analyst Katy Hubertysaid in a research note today.
Android revenue share reached 46.2 percent in 3Q13, for the first time exceeding iPad share of 45.6 percent. Android’s unit share grew to 66.7 percent from 58.5 percent;a year ago, largely driven by Samsung and Lenovo, while iPad share declined to 29.7 percent from 40.2 percent.
These numbers were reported before Apple shipped its new iPad Air which is expected to be a hot-seller through the rest of the year. Revenue figures also don't reflect profit and Apple is still widely-believed to make the most profitable devices of any tablet maker.