John Hughlings Jackson, (4 April 1835 - 7 October 1911), was an English neurologist.He was born at Providence Green, Green Hammerton, near Harrogate, Yorkshire, the youngest son of Samuel Jackson, a yeoman who owned and farmed his land, and the former Sarah Hughlings, the daughter of a Welsh revenue collector.

Jackson was an innovative thinker and a prolific and lucid, if sometimes repetitive, writer. Though his range of interests was wide, he is best remembered for his seminal contributions to the diagnosis and understanding of epilepsy in all its forms and complexities. His name is attached eponymously to the characteristic "march" of symptoms in focal motor seizures and to the so-called "dreamy state" of psychomotor seizures of temporal lobe origin. His papers on the latter variety of epilepsy have seldom been bettered in their descriptive clinical detail or in their analysis of the relationship of psychomotor epilepsy to various patterns of pathological automatism and other mental and behavioural disorders.

Jackson studied seizures, nervous-system disorders, and speech defects cause by brain disorders. He was a leading proponent of the idea that convulsions are a symptom, not a disease. Based on observation and autopsy, without animal experiments or even a microscope, he correctly determined that different bodily functions are controlled by specific regions of the cerebral cortex, and that some forms of epilepsy are caused by localized cortical disorders in the cerebrum. He was also among the first physicians to describe the relationship between ocular and cerebral disease.

Together with his friends Sir David Ferrier and Sir James Crichton-Browne, two eminent neuropsychiatrists of his time, Jackson was one of the founders of the important Brain journal, which was dedicated to the interaction between experimental and clinical neurology (still being published today)