Hildon is an application framework originally developed for mobile devices running the Linux operating system as well as the Symbian operating system. The Symbian variant of Hildon was discontinued with the cancellation of Series 90. It was developed by Nokia for the Maemo operating system. It focuses on providing a finger-friendly interface. It is primarily a set of GTK extensions that provide mobile-device–oriented functionality, but also provides a desktop environment that includes a task navigator for opening and switching between programs, a control panel for user settings, and status bar, task bar and home applets. It is standard on the Maemo platform used by the Nokia Internet Tablets and the Nokia N900 smartphone.

Maemo is a software platform originally developed by Nokia, now developed by the community, for smartphones and Internet tablets. The platform comprises both the Maemo operating system and SDK. Maemo played a key role in Nokia's strategy to compete with Apple and Android, but ultimately failed to surpass both companies.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 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.