In this study, it was aimed to examine the neuroprotective effects of ethanolic extracts of Chlorella variabilis YTU.ANTARCTIC.001and Chlorella pyrenoidosa OZCIMEN.001microalgae that were isolated from Antarctica in a H2O2-induced oxidative stress model using SH-SY5Y cell line. In this context, first, Antarctic microalgae were cultivated and characterized. It was determined that C. pyrenoidosa and C. variabilis had specific growth rates of 0.093 and 0.097day-1, respectively, and doubled their cell concentration in 7days. With the antioxidant and phenolic content analysis, it was found that 1mg/mL C. pyrenoidosa and C. variabilis ethanolic extracts had 33-37% radical scavenging activity and 102-107mg GAE/mg extract phenolic content, respectively. Then, the cytotoxic effects of the microalgae extracts on SH-SY5Y cells were assessed across a concentration range of 6.25-125µg/mL. The results indicated a concentration-dependent effect on cell viability, with no observed cytotoxicity within the tested range. Notably, the highest neuroprotective activity was recorded with C. variabilisextract at a concentration of 75µg/mL, which maintained cell viability at 73.7% ± 0.3. These findings showed the significant neuroprotective potential of C. pyrenoidosaandC. variabilisethanolic extracts, attributed to their substantial antioxidant properties and non-cytotoxic nature at effective concentrations. The promising neuroprotective efficacy of these extracts highlights their potential for therapeutic applications in neurodegenerative disease prevention and treatment.