Neurology has evolved into a distinct specialty, yet it remains deeply interconnected with numerous medical and surgical fields. This chapter explores the vital relationships between neurology and closely overlapping specialties, highlighting both historical roots and modern collaborative practices. Core extensions of neurology and shared understanding enhance diagnosis, management, and patient outcomes—including across neurosurgery, psychiatry, neuropsychology, neuroradiology, neurophysiology, neurorehabilitation, genetics, speech therapy, and palliative care. The chapter also reviews collaborative ties with internal medicine; cardiology; pediatrics; infectious diseases; pulmonology; nephrology; gastroenterology; dermatology; orthopedics; ophthalmology; Ear, Nose, and Throat; obstetrics; hematology; endocrinology; urology; and intensive care medicine. The chapter also emphasizes that future neurological care must be inherently multidisciplinary, leveraging the strengths of allied fields to optimize patient-centered outcomes. Therefore, neurologists must master their own discipline as well as navigate collaborations with surrounding specialties, adapting to diverse clinical environments worldwide. Recognizing, strengthening, and formalizing these interdisciplinary connections are critical steps toward advancing neurological science and care in an increasingly complex medical landscape.