The recent advances in the field of 2D hexagonal boron nitride (hBN) for realizing electronic and optoelectronic devices, including wearable and portable devices, have aroused scientific interest in this ultrathin material for a wide range of applications. Its exceptionally high thermal conductivity and temperature stability make it one of the most promising materials for next-generation high-performance gas sensors. Although a number of review articles on hBN have already been published focusing on its synthesis, properties, and functionalities, however, none of them has made a significant contribution to the field of gas sensing. Hence, in this review, we have analytically summarized the state-of-art advances in hBN based devices with a particular emphasis on gas sensors. Moreover, we have also explained the comprehensive physics of hBN based gas sensors. The recent technological advancements to overcome the inherent properties such as poor surface reactivity and low conductivity have also been thoroughly compiled. Finally, we have discussed some of the prominent challenges faced by hBN technology for developing practical gas sensors. © The Royal Society of Chemistry 2021.