Fernand Holweck (21 July 1890 – 24 December 1941) was a French physicist who made important contributions in the fields of vacuum technology, electromagnetic radiation and gravitation.

During his military service he worked under the wireless telegraphy pioneer Gustave-Auguste Ferrié at the Eiffel Tower radio station, and by 1914 he had produced his first patent, relating to thermionic tubes.

This pump, which utilised the drag of air molecules against a rotating surface, achieved vacuums as great as one millionth of a centimetre of mercury, was subsequently manufactured by the notable French scientific instrument maker, Charles Beaudouin.

Other important inventions included a highly sensitive and portable gravimetric pendulum, which was used in oil and mining exploration, and a widely used X-ray tube.

He also worked with the celebrated aviation pioneer and author Antoine de Saint-Exupéry, to solve practical problems in aircraft operation.