Maemo is an open-source Linux-based operating system for smartphones and tablets, developed by Nokia and improved with community effort.
The Maemo OS was initially designed for Nokia Internet Tablets, a lineup which started in 2005 and ended in 2008 with the Nokia N810 WiMax edition. These internet tablets feature similar chipsets to Nokia's high-end N-series and E-series smartphones, but lack the telephony, have a landscape UI, which runs on 4.1-inch touchscreens with the relatively high resolution of 800 x 480px.
Maemo is mostly based on open-source code and has been developed by Maemo Devices within Nokia in collaboration with many open-source projects such as the Linux kernel, Debian, and GNOME. Maemo is based on Debian GNU/Linux and draws much of its GUI, frameworks, and libraries from the GNOME project. It uses the Matchbox window manager and the GTK-based Hildon framework as its GUI and application framework.
The last iteration of Maemo was called Maemo 5 and was featured on the Nokia N900, which was not marketed as an Internet tablet. It had a telephony functionality, a 3.5-inch screen and a slide-out keyboard. A portrait user interface was introduced for the first time.
At the Mobile World Congress in February 2010, it was announced that the Maemo project would be merging with Moblin to create the MeeGo mobile software platform. Despite that, the Maemo community continued to be active, and in late 2012 Nokia began transferring Maemo ownership to the Hildon Foundation, which was replaced by a German association Maemo Community.
Since 2018, a new release called Maemo Leste is in development which is based on Devuan.