<p><i>Eruca sativa</i> Mill. is an underutilized crop for the production of oil. Evaluating the exact potential of <i>E. sativa</i> oil quantity and quality, and salinity-associated physiological adaptations with low-quality saline water would be helpful for making decisions about its large-scale cultivation on marginal lands. A lysimeter (drum-pot) experiment was conducted under a series of saline water irrigation (EC_iw 0.72, 4.02, 7.32, 10.42, and 13.43 dS.m⁻¹) and the physiological data was taken at the seed-filling stage. The results showed that all the growth and yield parameters declined under higher salinity. The linear regression model showed a 50% reduction in weights of shoots, siliquae, and seeds at irrigation salinity (EC_iw) of 13 dS.m⁻¹. Seed oil content was only significantly declined at higher salinity of EC_iw 13.43 dS.m⁻¹ compared to control. Palmitic and linoleic acids were increased from 4.66 to 6.06% and 9.76 to 13.7%, respectively; and erucic acid declined from 43.7 to 40.35% at higher salinity. Photosynthetic pigments, osmotic potential, K⁺/Na⁺ ratio, and CAT activity significantly declined; and RWC, soluble sugars, proline, Na⁺, K⁺, malondialdehyde, proteins and APX activity were significantly augmented with increasing salinity. The results demonstrate that <i>E. sativa</i> makes osmotic adjustments for survival under salinity and could be grown on marginal lands for industrial oil production.</p>