The breast tumor microenvironment (TME) promotes drug resistance through an elaborated interaction of TME components mediated by reactive oxygen species (ROS). Although there is massive accumulation of data concerning the targeting of the ROS, little is known about the ROS-responsive nanomedicine for targeting breast TME. This review submits the ROS landscape in breast TME, including ROS biology, ROS mediated carcinogenesis, and reprogramming of stromal and immune cells of TME. We also discussed ROS-based precision strategies for imaging TME, including molecular imaging techniques with advanced probes, multiplexed methods, and multi-omic profiling strategies. ROS-responsive nanomedicine also describes various therapies, such as chemo- dynamic, photodynamic, photothermal, sono-dynamic, immune, and gene therapy for BC. We expound ROS-responsive primary delivery systems for chemotherapeutics, phytochemicals, and immunotherapeutics. This review also presents recent updates on nanotheranostics for simultaneous diagnosis and treatment of BCs. We assume that a review on this advancing field will be beneficial to the development of ROS-based nano-theranostics for BC.