Ludwig von Tetmajer (14 July 1850, Krompachy, Upper Hungary - 1 February 1905, Vienna, Austria) was a professor at the Eidgenössischen Polytechnikum, the fore-runner of modern ETH in Zurich.

Tetmajer was a pioneer in the development of the research laboratories for determining the physical and mechanical properties of the construction materials and a co-founder of the Festigkeitsprüfungsanstalt, the modern Eidgenossische Materialprüfungs- und Forschungsanstalt (Empa) of Switzerland.

His cousins, novelist Kazimierz Przerwa-Tetmajer and painter Włodzimierz Tetmajer, belonged to the Polish branch of the family.

In 1867 he finished his secondary education cum laude and after a one-year preparatory study he enrolled at the Faculty of Engineering at the Eidgenössischen Polytechnikum in Zurich, Switzerland.

In 1873, he became an assistant of Carl Culmann from the chair of Statics at the Eidgenössischen Polytechnikum and later the same year became a Privatdozent for the Building Mechanics.