Dr. Julius Yemans Dewey (- ) was an American doctor of medicine and businessman in the state of Vermont during the 19th century. He was born in Berlin, Vermont. He attended Washington County Grammar School and then the University of Vermont.
His first wife and the mother of his children was Mary Perrin whom he married in 1825. She died young, however, and he had two later marriages without issue, to Susan Edson Tarbox and Susan Elizabeth Griggs Lilley.
He was a founder of the Christ Episcopal church of Montpelier. He served as a trustee of Norwich University. He was a founder of and later president of the National Life Insurance Company and he personally delivered the remittance for the company's first claim, prompting a public thank-you from the surviving family.