James Patrick Bernard Duffy (November 25, 1878 – January 8, 1969) was an American lawyer, jurist, and politician who served one term as a Democratic member of the United States House of Representatives from New York from 1935 to 1937.

He was admitted to the bar the same year and began practice in partnership with Republican James Breck Perkins, a member of Congress.

He abandoned the practice of law in 1914 acceding to his father's request to take over as manager of The Duffy-Powers Department Store, the family business.

In addition, Congressman Duffy's sister Constance Josephine married Bishop Thomas Francis Hickey's brother Jeremiah Griffin.

Duffy died at St. Anne's Home in Rochester, New York, on January 8, 1969, and was laid to rest in Holy Sepulchre Cemetery.