Biology of Sex Differences invites authors to submit articles exploring the mechanisms underlying sex differences in neurodegenerative diseases. This Collection seeks to highlight how biological sex influences the risk, progression, and treatment responses in conditions such as Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, and multiple sclerosis. Topics may include, but are not limited to, sex-specific variations in genetic risk factors, hormonal influences, immune responses, neuroinflammation, metabolic and vascular contributions, as well as pharmacological interventions and treatment outcomes. Submissions addressing gender differences should consider gender as a contributing factor, distinct from biological sex. The collection welcomes diverse article types, including original research, reviews, meta-analyses, perspectives, and commentaries. Through this Collection, we aim to advance understanding of the complex interplay between sex/gender and neurodegenerative diseases, fostering innovations in diagnosis, treatment, and prevention strategies. We encourage submissions from researchers across fields to contribute to this important area of investigation.