The General Radio Company was established by Melville Eastham in Cambridge, Massachusetts in 1915. The company was established under the assumption that measurement would be the basis of technical progress in electrical communication, as had been demonstrated in other fields of physics.

The company steadily grew and during the 1950s it became a major player in the automatic test equipment (ATE) business. They manufactured a line of testers for assembled printed circuit boards, lines of electrical component measuring equipment, sound and vibration measurement equipment, and RLC standards.

During the 1970s, the company gained success in its invention of computerised automated test equipment, and in 1975 they changed their name to GenRad.

In 1991, the startup, QuadTec, was created as a spinoff to GenRad's instrumentation division and precision product lines. In 2000, QuadTec sold the RLC standards, impedance decades, megohmmeters, digibridges, audio lines and stroboscope lines to IET Labs. Then in 2005, QuadTec further sold the Digibridge and Megohmmeter lines to IET Labs.

In 2001, GenRad was bought by Teradyne which ended the brand name. However, many of the products lived on through IET Labs.