Joseph Simon (February 7, 1851 - February 14, 1935) was a United States Senator from Oregon. Born in Bechtheim, Germany, he immigrated to the United States with his parents, who settled in Portland in 1857. He attended the public schools, studied law, was admitted to the bar in 1872, and commenced practice in Portland. He was a member of the city council from 1877 to 1880 and a State senator from 1880 to 1898, frequently serving as president. He was a member of the Republican National Committee from 1892 to 1896.
Simon was elected as a Republican to the U.S. Senate on October 8, 1898, to fill the vacancy in the term commencing March 4, 1897, and served until March 3, 1903; he was not a candidate for reelection. While in the Senate, he was chairman of the Committee on Irrigation and Reclamation of Arid Lands (Fifty-sixth and Fifty-seventh Congresses). He was mayor of Portland from 1909 to 1911, resumed the practice of law, and died in Portland in 1935; interment was in Beth Israel Cemetery.