Objective As an important monitoring target for gaseous effluents from nuclear facilities, the radioactive inert gas ⁸⁵Kr requires accurate measurement, which is crucial for nuclear safety and radiation protection. This study organized an inter-laboratory comparison activity for ⁸⁵Kr gamma-ray spectrometry measurements, with the aims of identifying potential problems in ⁸⁵Kr measurement and improving detection capabilities and proficiency. Methods Four laboratories participated in this comparison. Each laboratory employed gamma-ray spectrometry to measure the comparison samples, and the results were evaluated using the E_n value. Results The measurement results from all participating institutions were acceptable, with the maximum E_n value being 0.73. The results demonstrate that despite the low gamma-ray branching ratio of ⁸⁵Kr and its susceptibility to interference from the 511 keV positron annihilation peak, gamma-ray spectrometry can achieve reliable activity measurements of ⁸⁵Kr. Conclusion The comparison for ⁸⁵Kr gamma-ray spectrometry tested the capabilities of the participating laboratories in ⁸⁵Kr measurement. It promoted technical exchange and experience sharing among laboratories, laying a foundation for future comparisons involving more complex radioactive inert gases.