 1.Metal organic frameworks, MOFs, are highly ordered crystalline coordination polymers that have unique structures and properties, making them suitable for environmental contaminant detection. 2.Various MOF-based sensing platforms have been reported for the detection of anions, heavy metal ions, organic compounds, and gases, with promising performance in water and gas contaminant sensing. 3.By incorporating other functional materials, MOF-based composites can improve sensor performance, and current limitations and future directions are discussed. This article was authored by Xian Feng, Boyang Zong, and Shen Mao.