<p>The aspects of metrological assurance for the measurement of spectral characteristics of radiation receivers across a&#xa0;broad spectral range (from ultraviolet to infrared, including terahertz) are discussed. To date, no metrological support for measuring spectral sensitivity of radiation receivers with wavelengths exceeding 14 µm has been established, which prevented the use of these receivers for measuring terahertz radiation power in applications related to medicine, security, and climatology. To reproduce and transfer the unit of spectral sensitivity of radiation receivers in the wavelength range of 14–300 µm, traceable to an absolute cryogenic radiometer, a&#xa0;standard terahertz radiation receiver has been developed, manufactured, and studied. The principle of operation and the design of the developed receiver are described, and its metrological characteristics are examined. The components of uncertainty in the reproduction of the unit of spectral sensitivity of the standard terahertz radiation receiver are calculated. A&#xa0;budget of uncertainties during the reproduction of the unit of spectral sensitivity in the wavelength range of 14–300 µm is presented. A&#xa0;setup based on a&#xa0;monochromatic terahertz radiation source and the standard terahertz radiation receiver has been developed. This setup is intended for transferring the unit of spectral sensitivity to terahertz radiation receivers. The results of this study are of significant importance for various fields of science and technology, as measurements of spectral sensitivity are widely applied in astrophysics, lighting engineering, geophysics, biophysics, biology, medicine, agriculture, chemistry, metallurgy, etc.</p>