A double‐sided, high‐frequency response heat‐flux gauge has been developed which allows measurement of heat flux from dc to 100 kHz. The instrument is designed for heat‐flux magnitudes ranging from one to several hundred kW/m2at temperatures up to 400 °C and is independent of the test article material. The gauges consist of a metal film (1500 A˚) resistance thermometers sputtered on both sides of a thin (25 &mgr;m) polyimide sheet. The sheet, which can contain many gauges, is then adhesively bonded to a test article. The temperature difference across the polyimide is a direct measure of the heat flux at low frequencies, while a quasi‐1D analysis is used to infer the high‐frequency heat flux from the upper surface temperature history. The design criteria, construction and application techniques, and a novel, ratiometric calibration procedure are discussed in detail.