Matthias Ettrich (born 14 June 1972) is a German computer scientist and founder of the KDE and LyX projects.

Ettrich was born in Bietigheim-Bissingen, Baden-Württemberg, West Germany, and went to school in Beilstein while living with his parents in Oberstenfeld.

He is currently focused on advising start-ups and corporations on digital transformation and in sound technical decision-making.

Since LyX's main target platform was Linux, he started exploring different ways to improve the graphical user interface, ultimately leading him to the KDE project.

Ettrich founded KDE in 1996 when he proposed on Usenet a "consistent, nice looking free desktop environment" [sic] for Unix-like systems using Qt as its widget toolkit.