The special issue on Thioredoxin and Glutaredoxin systems, published in Antioxidants, presents 16 research articles exploring the roles of these redox systems in various biological processes. The issue covers topics such as the regulation of reactive oxygen species (ROS) in plant stress responses, the structural and functional properties of thioredoxin (TRX) and glutaredoxin (GRX) systems in plants and bacteria, and the involvement of these systems in nitrogen fixation and symbiotic relationships. The articles also discuss the physiological functions of methionine sulfoxide reductases (MSRs) in redox homeostasis and signaling, the structural analysis of TRX and GRX proteins, and the redox regulation of key enzymes in plant development and stress responses. The issue highlights the importance of TRX and GRX systems in maintaining cellular redox balance and their roles in various physiological processes, including photosynthesis, stress adaptation, and cellular signaling. The research underscores the significance of these systems in plant biology and their potential applications in agriculture and biotechnology. The special issue also includes studies on the redox regulation of enzymes such as monodehydroascorbate reductase and the impact of redox signaling on chlorophyll biosynthesis. Overall, the special issue provides a comprehensive overview of the current understanding of thioredoxin and glutaredoxin systems and their roles in cellular redox regulation and biological processes.The special issue on Thioredoxin and Glutaredoxin systems, published in Antioxidants, presents 16 research articles exploring the roles of these redox systems in various biological processes. The issue covers topics such as the regulation of reactive oxygen species (ROS) in plant stress responses, the structural and functional properties of thioredoxin (TRX) and glutaredoxin (GRX) systems in plants and bacteria, and the involvement of these systems in nitrogen fixation and symbiotic relationships. The articles also discuss the physiological functions of methionine sulfoxide reductases (MSRs) in redox homeostasis and signaling, the structural analysis of TRX and GRX proteins, and the redox regulation of key enzymes in plant development and stress responses. The issue highlights the importance of TRX and GRX systems in maintaining cellular redox balance and their roles in various physiological processes, including photosynthesis, stress adaptation, and cellular signaling. The research underscores the significance of these systems in plant biology and their potential applications in agriculture and biotechnology. The special issue also includes studies on the redox regulation of enzymes such as monodehydroascorbate reductase and the impact of redox signaling on chlorophyll biosynthesis. Overall, the special issue provides a comprehensive overview of the current understanding of thioredoxin and glutaredoxin systems and their roles in cellular redox regulation and biological processes.