Abstract: NaHS was used as an exogenous H₂S for this study to induce changes on the protein expression and morphological/physiological properties of wheat seedlings. Varied concentrations of NaHS (i.e., 0, 0.05, 0.10, 0.20, 0.40, 0.80, 1.60, and 3.20 mmol·L^-1) were incorporated in the medium solution for the experimentation. According to the effect on the seedling growth and based on their concentrations, 3 groups of the solutions were classified as (a) LC at 0.05 and 0.10 mmol·L^-1 that promoted the growth, (b) IC at 0.20, 1.60, and 0.40 mmol·L^-1 that inhibited the growth, and (c) HC at 0.80 and 3.20 mmol·L^-1 that harmed the growth. When LC was applied, the height, root length, and fresh or dry weight of the plants increased significantly, while the application of HC produced the opposite effects. Furthermore, moisture and leaf chlorophyll contents of the plants were significantly affected by the NaHS concentration. There were also significant correlations observed between the biomass and physiological characteristics, according to a principal component analysis.