Paclobutrazol (PBZ) is one of the most important triazole compounds. This compound increases plant tolerance to environmental stresses. The present study aimed to investigate the effects of PBZ on morphological and biochemical traits of euonymus (Euonymus japonicas) exposed to NaCl stress. Plants were treated with three levels of PBZ (0, 500 and 1000 mg L-1) and four levels of NaCl (0, 50, 100, 150 mM). Morphological characteristics, electrolyte leakage (EL), chlorophyll content, and antioxidant enzyme activity were changed by the treatment with PBZ and NaCl stress. As compared to the control plants, PBZ at the rates of 1000 and 500 mg L-1 decreased height by 22.8% and 10.44%, respectively. The highest number of lateral shoots was recorded at 1000 mg L-1 PBZ (no salt treatment). The interaction of salinity and PBZ was significant for shoot fresh weight. At 150 mM NaCl + 1000 mg L-1 PBZ, shoot fresh weight was increased by 30% compared to 150 mM NaCl. The PBZ-treated plants had highersuperoxide dismutase (SOD) activity than those not treated with PBZ. PBZ at the rate of 1000 mg L-1 was the best treatment for increasing the activity of this enzyme. PBZ mitigated the salinity stress and reduced EL of euonymus. Compared with 150 mM NaCl alone, EL was decreased by 24.4% in the plants treated with 1000 mg L-1 PBZ + 150 mM NaCl. According to the results, it can be concluded that PBZ can be effective in improving the tolerance of euonymus to 150 mM NaCl. Manuscript profile