2,4-Dichlorophenoxyacetic acid (2,4-D) is currently the second most used herbicide in the world. Previous research from our laboratory has shown that 2,4-D has neurotoxic effects in animal models and may be linked to cognitive and psychiatric disorders associated with alterations in dopaminergic systems. Our laboratory was the first to demonstrate that changes in the Wnt/β-catenin pathway in PFC are associated with an increase response to cocaine. The aim of this study was to investigate the impact of oral exposure to 2,4-D during adolescence on cocaine vulnerability at behavioral, neurochemical, and molecular levels. From post-natal day (PND) 30 to PDN49, female and male rats, were fed with food exposed to 2,4-D (25 mg/kg/day) or to vehicle. On PND 50, total locomotor activity was recorded for 100 minutes following a cocaine a cocaine (5 mg/kg i.p) or saline injection. Twenty-four hours later, animals were sacrificed and PFC tissue was collected for western blot analysis. Results showed that in female rats exposed to 2,4-D cocaine induced a significantly higher locomotor activity compared to all other groups. Moreover, β-catenin expression in PFC was increased in these females. No significant differences at behavioral or molecular levels were found in males. In conclusion, these findings suggest that exposure to 2,4-D enhances susceptibility to cocaine in adolescent female rats, potentially through modulation of the Wnt/β-catenin pathway in the PFC.