Zoltán Lajos Bay (July 24, 1900 in Gyulavári – October 4, 1992 in Washington, D.C.)[1] was a Hungarian physicist, professor, and engineer who developed technologies, including tungsten lamps and microwave devices.

In 1923 at Tungsram Ltd., a research laboratory was established for improving light sources, mainly electric bulbs.

[1] The head of that laboratory was Ignác Pfeifer, whose research staff included Zoltán Bay, along with Tivadar Millner, Imre Bródy, György Szigeti, Ernő Winter, and many others.

[1] György Szigeti worked together with Zoltán Bay on metal-vapor lamps and fluorescent light sources.

In 1998, the State of Israel recognized him as among the Righteous Among the Nations and listed his name at Yad Vashem as rescuer number 6497.