The interplaying defensive roles of silicon (Si) and proline (Pro) in improving growth and yield attributes, physio-biochemical attributes, and antioxidant defense systems in common bean plant grown under saline (NaCl) and/or cadmium (Cd2+) stress were assessed. Seed were sown in plastic pots filled with sand-free ions as a growing medium that watered with a ½-strength Hoagland's nutrient solution. Twenty five days after planting, pots were split into 4 plots; control (no stress), 150 mM NaCl (salt stress), 1.5 mM Cd2+ in CdCl2 (Cd2+ stress), and 100 mM NaCl + 1.0 mM Cd2+ (salt + Cd2+ stress). Four treatments; foliar spray with distilled water, 6 mM Si (in K2SiO3.nH2O) solution, 6 mM Pro solution, and a combination of Si and Pro were allotted under each of the 4 plots. The experimental layout was a completely randomized design with 15 replicates. Compared to control, NaCl or Cd2+ stress significantly (P ≤ 0.05) reduced plant growth and yield attributes, leaf contents of chlorophylls, carotenoids, N, P, and K+, K+/Na+ ratio, RWC, MSI, Pn and Tr, while elevated significantly leaf EL, leaf contents of proline, soluble sugar, glutathione, MDA, Na+, and root, leaf and pod contents of Cd2+. The activities of antioxidant enzymes were also raised. The combined stress (NaCl + Cd2+) was more influential. Addition of Si and/or Pro for common bean plants under NaCl and/or Cd2+ stress significantly enhanced all investigated attributes of physiology, morphology, and biochemistry, and further increased the activities of antioxidant enzymes. Supplementation of Si + Pro was the best treatment having more positive influential, especially reducing the Cd2+ content in Phaseolus vulgaris pods to the limits (0.27 mg kg−1) for legumes. Therefore, this combined treatment is recommended to use for alleviating environmental stress effects, especially salinity and Cd2+ for common bean production. •Interplay between Si and proline improved growth and yield of salt- and Cd2+-stressed common bean plants.•Enzymatic and non-enzymatic antioxidants activities were improved by the interplay between Si and proline.•Si+ proline application effectively restored nutrient elements due to maintaining cell water content in stressed bean plants. A diagram shows the effect of NaCl-salinity and/or Cd2+ stress and interplay between Si and proline on growth and yield, physio-biochemical attributes, and antioxidant defense systems in stressed commen bean plants. Display omitted