This study was conducted to determine the effects of seed priming with ascorbic acid (AsA) on germination and seedling characteristics of rapeseed (Brassica napus L.) under different salinity levels. To this end, the study examined five salinity levels (0.20, 5.0, 10.0, 15.0, and 20.0 dS m-1 NaCl) and four priming doses (control, 0.5, 1.0, and 2.0 mM ascorbic acid). Salt stress negatively affected germination and some plant growth traits, such as radicle length (RL), plumule length (PL), radicle fresh weight (RFW) and plumule fresh weight (PFW), finally germination percentage (FGP), germination index (GI), mean germination time (MGT) and seedling vigor index (SVI). On the other hand, priming with AsA positively affected all parameters except FGP, PFW and salt tolerance index (STI). According to the interaction of salinity stress and priming, the highest values for GI (125.3), MGT (1.63 days), PFW (0.35 g), and STI (139.3%) were obtained at 5.0 dS m-1 salinity stress and 1.0 mM AsA dose. However, the highest value was obtained for RL (10.6 cm) and SVI (1170.7) at the control treatment and 0.5 mM AsA dose, whereas the highest value was obtained for PL (1.7 cm) at the control treatment and 1.0 mM AsA dose. Ascorbic acid at low doses (0.5 and 1.0 mM) had a positive effect on seedling germination and growth traits, while higher concentrations had a toxic effect on germination. Thus, it was concluded that priming rapeseed seeds with an AsA dose of 0.5 mM could reduce the restrictive impact of salinity stress on seed germination and seedling improvement. Further studies on the yield and growth parameters of rapeseed under salt stress by AsA application are recommended.