It's the second month Android has taken the top spot on the ad network, having surpassed former king iOS for the first time in December.
Losing ground
It doesn't look as if Apple will be fighting back any time soon, either.
Android's share is now almost double that of iOS, rising by 8 percentage points as Apple lost ground iOS falling by 4 percent to 28 percent in comparison.
BlackBerry's share is also being squeezed, down 2 percentage points to 14 percent.
Dual attack
However, when it comes to actual devices on Millennial's network, Apple remains at the top of the tree, with iPhone and iPod touch accounting for more than a 26 percent share of the market.
HTC also enjoyed a strong month according to Millennial's figures, with the OEM growing 36 percent to claim second spot in the rundown of top manufacturers.
The firm holds around a 5 percent lead over Android rival Samsung, with the Korean firm's Galaxy S and Epic handsets featuring in Millennial's top 30 devices for the first time.
You can read the full Mobile Mix report for January on Millennial Media's website.
