John Robert Murdock (born April 20, 1885) was a Democratic member of the United States House of Representatives from Arizona. He represented Arizona’s 1st Congressional District and served as a federal legislator during the mid-twentieth century. His congressional career is documented under the Biographical Directory of the United States Congress identifier M001081.

Murdock began his service in the U.S. House of Representatives on January 5, 1937, and remained in office until January 3, 1953. Over this sixteen-year span, he served eight terms as a Representative from Arizona’s 1st District. During this period he was a member of the Democratic Party and held the formal role of Representative, after which he left office and is recorded as a former member of Congress.