Basil ( Ocimum basilicum L.) is an annual medicinal and aromatic plant belonged to lamiaceae family. In traditional medicine, it is applied as an herbal medicine for headache, cough as well as food flavors. It is cultivated in Iran and other countries around the world as a medicinal and aromatic plant. One of the main issues in its large scale cultivation is its vulnerability to weeds. Unfortunately, no herbicide has been register for weed control in Iran. Therefore, in this research, the possibility of using herbicide Bentazone, a photosynthetic inhibitor herbicide, was investigated under salicylic acid pretreatment to control weeds in basil under field condition. In other words, the present research aims to test the hypothesis that pretreatment of salicylic acid could increase the tolerance of basil plant to bentazone herbicide. This experiment was arrange in factorial based in a randomized complete block design with four replications at Isfahan University of Technology (Lavark) Research farm from April to October 2018. Treatments involved three concentrations of salicylic acid (control (0),0.5, 1 and 1 mM) and six concentrations of Bentazone herbicide (control (zero), X50, 0.75, 0.75, X, X25.1 and X5.1 where X is equivalent of the recommended dosage (1440 g of active ingredient per hectare). Phytotoxicity damage percentage, chlorophyll a, chlorophyll b, total chlorophyll and carotenoids contents, photosystem II quantum efficiency, leaf relative water content (RWC), membrane stability index (MSI), hydrogen peroxide (H2O2), malondialdehyde content Aldehyde (MDA), antioxidant enzymes activities including ascorbate peroxidase (APX), catalase (CAT), guaiacol peroxidase (GPX), plant height, shoot dry weights, essential oil content, proline content, 1000-grain weight and weed infestation as density of weeds Chenopodium album and Amaranthus retroflexus per unit area were evaluated. Bentazone herbicide alone in the recommended rate and increased doses reduced chlorophyll and carotenoids contents, photosystem II quantum efficiency, relative leaf water content, membrane stability index, shoot dry weights and 1000 grain weight. At the same time it increased the activity of antioxidant enzymes (catalase, ascorbate peroxidase and guaiacol peroxidase), malondialdehyde, hydrogen peroxide and proline content. Application of salicylic acid at both concentrations (0.5 and 1 mM) improved the investigated traits and tolerance to oxidative stress induced by herbicide application. Meanwhile, pretreatment of basil with 0.5 mM salicylic acid significantly improved membrane stability, relative leaf water content, plant height and 1000 grain weight and prevented carotenoids degradation under herbicide application. Regarding the results of the percentage of weeds burning in the third week after Bentazone herbicide treatment, recovery of the damaged tissues in the plant was observed, which indicates that Basil is tolerant to this herbicide. The rate of damage reduction at the recommended dose of bentazone herbicide and 0.5 mM salicylic acid level was more significant than other treatments. In addition, the combination of salicylic acid with herbicide increased the growth and competitiveness of basil against weeds ( Chenopodium album and Amaranthus retroflexus ) and thus improved weed control efficiency. However, foliar spray with salicylic acid at 0.5 mM concentration had a greater effect on reducing weeds density per unit area. As a whole, the results showed that exogenous salicylic acid can reduce the damage caused by the application of bentazone on basil and increase the efficiency of herbicides on weed control. Keywords: Basil, Oxidative Stress, Bentazone, Salicylic Acid, Chenopodium album ,Amaranthus retroflexus.