Under the uncongenial growth condition imposed by salts in the edaphic environment, several biochemical changes take place in plants, which help them to survive under such a hostile environment. In the present study, an attempt has been made to obtain basic information about the effect of salt stress on relative membrane injury, lipid peroxidation content and reactive oxygen species content in isabgol (Plantago ovata Forsk.) genotypes. The changes in relative membrane injury, lipid peroxidation content and reactive oxygen species (ROS) content of P. ovata genotypes viz. GI-2, HI-96, PB-80 and HI-5 were studied under NaCl salt stress at different EC levels viz. control (without salt), 5 and 10 dS/m of nutrient supplemented NaCl salt solutions in sand filled polythene bags during 1st week of November 2022 in the Department of Botany Government College, Hisar. RMI, lipid peroxidation (MDA content) and ROS content of leaves increased with increasing EC levels in all the isabgol genotypes as studied at 58 days after showing. The highest increase in RMI was found in the genotype PB-80 and lowest in the genotype GI-2 at higher (10 dS/m) EC level over control. Increase in lipid peroxidation content which was measured in terms of MDA content was found highest in the genotype PB-80 while the lowest increase was detected in the genotype HI-5 at higher level (10 dS/m) of salt stress over control. Highest enhancement in ROS content of leaves in the genotype PB-80 and lowest increase in the genotype GI-2 was observed at higher (10 dS/m) EC level over control. The relative order of these parameters in various genotypes under salt stress was PB-80 greater than HI-5 greater than HI-96 greater than GI-2.