Linear alkyl benzene sulfonate is a group of anionic detergents widely used in domestic and industrial applications. It causes adverse effects by mixing with aquatic environments. Chemicals mixed with aquatic environments affect fauna and flora at different levels. This study was carried out to determine the toxicity of linear alkyl benzene sulfonate on the larvae of tarek living in the Van Lake basin, which has economic and ecological value. The chemical was administered at concentrations of 0.0, 0.6, 1.2, 1.8, 2.4, 3.0 mg L-1 in the acute test and 1.2, 2.4 mg L-1 in the chronic test. Tests were carried out using 100 larvae in each group. Bioassay were carried out at a mean temperature of 20.9 ± 0.4 °C. A median lethal concentration of 4.883 (4.099‒6.482) mg L-1 at 96 hours was calculated for the larvae. It was determined that glutathione content, superoxide dismutase and glutathione S-transferase activity decreased significantly at 1.2 mg L-1 and increased significantly at 2.4 mg L-1 compared to control. It was observed that the malondialdehyde content increased significantly depending on the increase in chemical concentration. Linear alkyl benzene sulfonate is toxic to tarek larvae in terms of measured biochemical parameters.