Reactive Oxygen Species (ROS) is the collective term used for the extremely reactive molecules that are important mediators in physiological processes as well as the development of various disease conditions. Normal cells maintain a delicate equilibrium, known as redox homeostasis, between antioxidants and ROS levels. Any imbalance in the redox homeostasis of the body results in oxidative stress which can result in inflammation, necrosis, apoptosis, cell death, and eventually a disease state. Enhanced ROS levels are a key feature in cancer cells that is being explored for developing reactive oxygen species-sensitive biomaterials. The distinct variation in redox potential between normal cells and tumour cells is one of the major physiological differences between them, that has enabled the development of ROS-sensitive nanomaterials for cancer therapy. ROS-sensitive nanomaterials are sensitive to the physiological variations in the cells, like high levels of hydrogen peroxide and glutathione in the cancer cells. ROS-responsive nanomaterials have the unique property of modulating microenvironmental redox conditions in cancer cells. ROS-sensitive material can work either by scavenging the ROS or by simulating the cellular antioxidants, leading to cancer cell cytotoxicity. These ROS-sensitive nanomaterials can simulate the human body's natural antioxidants like, superoxide dismutase and peroxidase. Thus, ROS-sensitive nanomaterials hold promise as a potential platform for the treatment of cancer. The present review will cover the importance of ROS in cancer, the different types of ROS-sensitive nanomaterials available and their therapeutic application in cancer therapy.