Lingxiao Xue, Yanyan Li, Yonghui Deng
Rapid advances in sensing technologies are transforming how humans monitor and interact with their surroundings, driving progress in fields spanning environmental protection, industrial safety, healthcare, food quality control, and intelligent living systems. Within this technological landscape, metal oxide semiconductor (MOS) sensors have emerged as a particularly promising platform, offering high sensitivity, fast response, low cost, and facile integration into diverse device architectures. Recent years have witnessed rapid progress in multicomponent porous MOS sensors, which leverage synergistic effects between different components and hierarchical porous architectures to achieve superior sensing performance. This review provides a comprehensive overview of multicomponent porous MOS gas sensors, encompassing fundamental sensing mechanisms, performance evaluation parameters, and fabrication processes. Particular emphasis is placed on advanced strategies for performance enhancement, including the construction of mesoporous architectures, elemental doping, noble metal functionalization, and heterojunction engineering. Furthermore, recent progress in practical applications is summarized, covering industrial and public safety, environmental monitoring, food freshness evaluation, and disease diagnosis. Finally, future development trends and critical challenges are discussed, highlighting opportunities in high‐throughput synthesis, machine learning‐assisted material design, low‐temperature flexible sensing, multi-parameter intelligent detection, and scalable device integration. This review aims to provide a systematic framework and forward‐looking perspective to inspire the rational design and technological advancement of next‐generation multicomponent MOS gas sensors.