Ocean warming facilitates the poleward expansion of invasive species. However, successful establishment in colder environments depends on their ability to tolerate low temperatures. Therefore, it is critical we understand the molecular mechanisms underlying cold tolerance for predicting invasion dynamics. However, the physiological and biochemical pathways underlying thermal responses can be sex specific, which is often overlooked. Such gaps can compromise management strategies aimed at predicting invasive species’ trajectories, fecundity, and recruitment rates. The European green crab Carcinus maenas is an invasive species worldwide, and its competition and predation threaten biodiversity, marine ecosystem functioning, and economically important species such as bivalves and lobster. The invasion capacity of the green crab is facilitated by its high tolerance to environmental variation. In this study, we investigate the cellular mechanisms that enable C. maenas to tolerate cold conditions and colonise new habitats in the Northwestern Atlantic Ocean, while considering sex differences. Using stress biomarkers, we assessed the cellular stress response of C. maenas experimentally exposed to temperatures in the lower range of its thermal niche to evaluate how these mechanisms shape cold tolerance. Preliminary results indicate that females display enhanced cellular stress responses compared to males. However, stress biomarkers remain consistent across temperatures (2, 6, 10 °C), suggesting green crabs are tolerant to temperatures as low as 2 °C. Our results support the use of molecular tools to monitor and better predict the potential for polewards expansion of green crabs and help design better strategies to limit its ecological and economic impacts.