Oxidative stress in the brain is associated with the development and progression of neurological disorders, posing antioxidant nutrients as an effective strategy for protecting neuronal cells and potentially slowing cognitive decline. Bioactive compounds from natural sources with antioxidant effects promote brain health. Among various natural compounds, astaxanthin (ASX), a potent red-pigment carotenoid found in various microorganisms and marine animals, is well recognized for its potential health benefits. In this review, we highlight the promising neuroprotective effects of ASX through cellular experiments and animal models. This review can provide novel insights on the therapeutic potential of ASX through its antioxidant, anti-inflammatory, and anti-apoptotic effects against neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease. In addition to demonstrating the neurotrophic effects of ASX on structural and functional changes in hippocampal neuronal plasticity, this review also discusses its synergistic potential with other interventions, such as exercise.