Dr. Wilder Graves Penfield C.C.,Ph.D (January 25/26, 1891 - April 5, 1976) was a American-born Canadian neurosurgeon.

He was born in Spokane, Washington, and studied at Princeton University before winning a Rhodes Scholarship to Oxford University and obtaining his medical degree from Johns Hopkins University. He spent several years training at Oxford (where he knew William Osler), and in Spain, Germany and New York.

Penfield was a groundbreaking researcher and devoted surgeon. He discovered the connections between different areas of the brain and the various limbs and organs, mapping both the sensory and the motor cortex. He also discovered that electrode stimulation could lead to vivid recall of memories.

During his life he was called "the greatest living Canadian." He devoted much thinking to the functionings of the mind, and continued until his death to contemplate whether there was any scientific basis for the existence of the human soul.

He moved to Montreal in 1928 to teach at McGill University and became the city's first neurosurgeon. In 1934 became the first Director of McGill University's Montreal Neurological Institute and the associated Montreal Neurological Hospital , which he helped establish with funding from the Rockefeller Foundation. He retired in 1960.

In 1967 he was made a Companion of the Order of Canada.

In 1994 he was inducted into the Canadian Medical Hall of Fame.