The cotton bollworm, Helicoverpa armigera (Hübner), is one of the important insect pests of cotton throughout the world. Considering the adverse effects of chemical pesticides, it is necessary to find eco-friendly substitute agents for managing insect pests, including H. armigera. Plant-derived insecticides have been introduced as suitable candidates to replace detrimental synthetic chemicals. In this study, the toxicities of water, ethanol, and n-hexane extracts of eucalyptus and thyme, as well as their wettable powder formulations, against H. armigera larvae were investigated. The treated larvae represented different degrees of abnormalities, such as larva-pupa intermediate and pupa-adult stages in their different ages until they turned into pupae and completed the breeding cycle. The results showed that the considered formulations of extract of n-hexane and ethanol, and concentrations had significant effects on the mortality rates of the larvae (P≤0.05) but the interaction of extracts and concentrations was not significant. The mortality rates were enhanced by increasing the tested concentrations. The LC₅₀ values (lethal concentrations to kill 50% of the tested insects) were 343.758% (water), 10.171% and 23.264% (ethanol), and 0.404% and 0.490% (n-hexane) for the eucalyptus and thyme extracts within 24 hours, respectively, indicating higher toxicities of n-hexane extracts. The LC₅₀ values of wettable powder formulations of the thyme and eucalyptus extracts were 120.68% and 177.75% (water) and 36.17% and 74.65% (ethanol), respectively, which represented the greater toxicities of these types of formulations. Therefore, the wettable powder formulations of ethanol and water extracts of thyme were more toxic than their solution formulations. Based on the results of this study, wettable powder formulation of eucalyptus and thyme extracts had promising potential for H. armigera management.