 Metal organic frameworks, MOFs, are a type of crystalline coordination polymer composed of metal ions or clusters and organic ligands. These materials have been used in environmental sensing due to their unique structure and properties such as high surface area, tailored pore size, and high catalytic activity. Recent advances in MOF-based environmental sensors include optical, electrochemical, and field effect transistors. These sensors have demonstrated excellent performance in detecting contaminants in water and air, and they can be further improved by incorporating other functional materials. Additionally, MOF-based composites can enhance the sensing capabilities of these devices. Finally, there are still many challenges and opportunities for MOF-based environmental sensors. This article was authored by Xian Feng, Boyang Zong, and Shan Mao.