This review discusses the regulation of reactive oxygen species (ROS) in crop plants under abiotic stress conditions such as drought, cold, salt, and heat. ROS, including hydrogen peroxide (H₂O₂), superoxide anions (O₂•−), hydroxyl radical (OH•), and singlet oxygen (¹O₂), are by-products of physiological metabolism and are crucial for plant stress responses. The review highlights the importance of ROS in signal transduction and the coordination of ROS production and scavenging pathways to maintain non-toxic levels of ROS. Key proteins involved in ROS regulation and abiotic stress tolerance, such as NADPH oxidases, transcription factors, and ROS-scavenging enzymes, are discussed. The role of plant hormones like abscisic acid (ABA) and brassinosteroids (BRs) in regulating ROS homeostasis and stress responses is also covered. The review concludes with an overview of current knowledge about ROS regulation in crop plants and the challenges in improving abiotic stress tolerance through ROS regulation.This review discusses the regulation of reactive oxygen species (ROS) in crop plants under abiotic stress conditions such as drought, cold, salt, and heat. ROS, including hydrogen peroxide (H₂O₂), superoxide anions (O₂•−), hydroxyl radical (OH•), and singlet oxygen (¹O₂), are by-products of physiological metabolism and are crucial for plant stress responses. The review highlights the importance of ROS in signal transduction and the coordination of ROS production and scavenging pathways to maintain non-toxic levels of ROS. Key proteins involved in ROS regulation and abiotic stress tolerance, such as NADPH oxidases, transcription factors, and ROS-scavenging enzymes, are discussed. The role of plant hormones like abscisic acid (ABA) and brassinosteroids (BRs) in regulating ROS homeostasis and stress responses is also covered. The review concludes with an overview of current knowledge about ROS regulation in crop plants and the challenges in improving abiotic stress tolerance through ROS regulation.