Abstract: Atomic layer deposition (ALD) is a high-precision thin film deposition technique renowned for its sub-nanometer thickness control, exceptional uniformity, and unique three-dimensional conformality. This capability enables uniform film growth on complex nanostructures and high-aspect-ratio surfaces. With the advancement of gas sensor technology, ALD has demonstrated broad application prospects in the preparation and regulation of gas sensing materials, particularly in the thin films, nanostructures, heterojunctions, and nanoparticle loaded structures. By enabling atomic-level control over film thickness and composition, ALD significantly enhances the sensing performance. In this review, we summarize recent key progress in the application of ALD technology to gas sensors. The current research challenges and future prospects for ALD in this field have been discussed.