LXDE was written in the C programming language, using the GTK 2 toolkit, and runs on Unix and other POSIX-compliant platforms, such as Linux and BSDs.

[3] The project was started in 2006 by Taiwanese programmer Hong Jen Yee (Chinese: 洪任諭; pinyin: Hóng Rènyù), also known as PCMan, when he published PCManFM, a new file manager and the first module of LXDE.

Dissatisfied with GTK 3,[9] Hong Jen Yee experimented with Qt in early 2013[10] and released the first version of a Qt-based PCManFM on 26 March 2013.

[16] GTK 3 versions have already been developed for the following components: LXAppearance, LXAppearance-ObConf, LXDE-common, LXDE-icon-theme, LXDM, LXhotkey, LXInput, LXLauncher, LXPanel, LXRandR, LXSession, LXTask, LXTerminal, Openbox, PCManFM.

As of July 2019 LXTerminal release is based on GTK 3 to avoid dependencies on the old VTE lib.