The ketogenic diet (KD) is increasingly recognized as a promising therapeutic strategy for neurodegenerative disorders because of its multifaceted impacts on key pathophysiological mechanisms. This review explores the molecular pathways through which KD may protect against neurodegeneration, including the use of ketone bodies as alternative energy substrates, reduction of oxidative stress and inflammation, modulation of autophagy and protein aggregation, and impact on the gut microbiome. The potential benefits of KD are explored across neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, and multiple sclerosis, based on both preclinical and clinical evidence that supports its feasibility. However, challenges in long-term safety, patient adherence, and clinical practicality limit its widespread adoption. This review underscores the potential of KD for treating neurodegeneration on the basis of current scientific evidence while highlighting the need for further research to optimize its application and address existing gaps.