Julius Kahn (February 28, 1861 – December 18, 1924) was a United States Congressman who was succeeded by his wife Florence Prag Kahn after his death. Kahn was born in Kuppenheim, in the Grand Duchy of Baden, in what would become Germany.
He immigrated to the United States with his parents, who settled in California in 1866. After studying law in San Francisco, he was elected a member of the State Assembly in 1892 and admitted to the bar in January 1894. He has been described by the American Jerusalem as "among the most influential Jews in San Francisco—as well as national–civic life, from the middle of the 19th century into the 1930s".
He was elected as a Republican to the 56th and 57th Congresses (March 4, 1899 - March 3, 1903). Although he unsuccessfully contested the election of Edward J. Livernash to the 58th Congress, he was elected to the 59th and to the nine succeeding Congresses and served from March 4, 1905 until his death in 1924.
During his time in the House of Representatives he was noted as an advocate of military preparedness. He helped draft and secure the passage of the National Defense Act of 1916, the Selective Service Act of 1917, and the National Defense Act of 1920. He served as chairman of Committee on Military Affairs (66th-68th Congresses). Representative Kahn also authored the Kahn Exclusion Act, ultimately enacted as the Alien Exclusion Act, telling Congress that "I submit if the Chinese people themselves would deal honestly with us, and if they resorted less to trickery and duplicity to circumvent our laws, then there would be no need of closing up all possible loopholes in the law with the seemingly severely restrictive measures that the Chinese themselves make necessary."
At the time of his death, he had been re-elected to the 69th Congress. His wife, Florence Prag Kahn, succeeded him in Congress and served until 1937. He was buried in the Home of Peace Cemetery in Colma, California. A well-known playground in San Francisco was named in his honor.
The Western Jewish History Center, of the Judah L. Magnes Museum, in Berkeley, California has a large collection of family papers, documents, correspondence, and photographs relating to Julius Kahn and to his wife, Florence Prag Kahn.