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This study aimed to test the role of hydrogen sulfide (H₂S) in the responses regarding the nitric oxide- (NO) and sulfur (S)-mediated improvement in photosynthesis and growth under cadmium (Cd) stress in mustard (<i>Brassica juncea</i> L. cv. Giriraj), and integrate the mechanisms of S, nitrogen (N), and antioxidant metabolism. The plants grown with Cd (200 mg Cd kg⁻¹ soil) exhibited reduced assimilation of S and N and diminished photosynthetic performance, which was associated with higher Cd accumulation-induced excess reactive oxygen species (ROS) production. The application of 100 μM of sodium nitroprusside (SNP, a NO donor) together with a more prominent concentration of S resulted in increased photosynthetic S- and N-use efficiency, production of non-protein thiols and phytochelatins, efficiency of enzymatic (superoxide dismutase, ascorbate peroxidase, and glutathione reductase), non-enzymatic antioxidants (ascorbate and glutathione) limiting Cd accumulation and, thus, reduced oxidative stress (superoxide radical, hydrogen peroxide, and thiobarbituric acid reactive species content). The benefit of NO together with S was manifested through a modulation in H₂S production. The use of 100 μM of hypotaurine (HT; H₂S scavenger) or 100 μM of cPTIO (2-4-carboxyphenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) in plants treated with NO plus S reversed the action of NO plus S, with a higher reduction in photosynthesis and growth with the use of HT, suggesting that H₂S plays a significant role in the NO- and S-mediated alleviation of Cd stress. The interplay of NO and ES with H₂S may be used in augmenting the photosynthesis and growth of Cd-grown mustard plants.