The thioredoxin (Trx) system is a key player in the survival and adaptation of Clostridia, particularly Clostridioides difficile, to various environmental stresses. This study reveals that C. difficile possesses multiple Trx systems, each with distinct roles in stress response, sporulation, and metabolic processes. The Trx system consists of thioredoxin (TrxA) and thioredoxin reductase (TrxB) proteins, which work together to reduce disulfide bonds and repair oxidized proteins. In C. difficile, three TrxA and three TrxB proteins are present, with TrxB1 and TrxB2 being NAD(P)H-dependent reductases, while TrxB1 also functions as a ferredoxin-dependent reductase. The Trx systems are regulated by different sigma factors, with TrxA1B1 being controlled by σB and σG during sporulation. The TrxA1B1 system is crucial for spore survival to hypochlorite and proper germination in the presence of oxygen. The third Trx system, involving TrxA3 and TrxB3, is involved in glycine catabolism and sporulation through the recycling of glycine-reductase, a key enzyme in Stickland pathways. The multiplicity of Trx systems in Clostridia likely meets specific needs for adaptation to stress, sporulation, and metabolic pathways. This study highlights the importance of Trx systems in the survival and pathogenicity of C. difficile, providing new insights into the physiology of this anaerobic gut pathogen.The thioredoxin (Trx) system is a key player in the survival and adaptation of Clostridia, particularly Clostridioides difficile, to various environmental stresses. This study reveals that C. difficile possesses multiple Trx systems, each with distinct roles in stress response, sporulation, and metabolic processes. The Trx system consists of thioredoxin (TrxA) and thioredoxin reductase (TrxB) proteins, which work together to reduce disulfide bonds and repair oxidized proteins. In C. difficile, three TrxA and three TrxB proteins are present, with TrxB1 and TrxB2 being NAD(P)H-dependent reductases, while TrxB1 also functions as a ferredoxin-dependent reductase. The Trx systems are regulated by different sigma factors, with TrxA1B1 being controlled by σB and σG during sporulation. The TrxA1B1 system is crucial for spore survival to hypochlorite and proper germination in the presence of oxygen. The third Trx system, involving TrxA3 and TrxB3, is involved in glycine catabolism and sporulation through the recycling of glycine-reductase, a key enzyme in Stickland pathways. The multiplicity of Trx systems in Clostridia likely meets specific needs for adaptation to stress, sporulation, and metabolic pathways. This study highlights the importance of Trx systems in the survival and pathogenicity of C. difficile, providing new insights into the physiology of this anaerobic gut pathogen.