Alexander G. Cattell (February 12, 1816 - April 8, 1894) was a United States Senator from New Jersey. Born in Salem, New Jersey, he received an academic education, and engaged in mercantile pursuits in Salem until 1846. He was elected to the New Jersey General Assembly in 1840, and served as clerk from 1842 1844. He was a member of the State constitutional convention in 1844 and moved to Philadelphia in 1846, where he engaged in business and banking. He was a member of the Philadelphia Common Council from 1848 to 1854, organized the Corn Exchange Bank, and was its president from 1858 to 1871. He moved to Merchantville, New Jersey in 1863 and was elected as a Republican to the U.S. Senate to succeed John P. Stockton, whose seat was declared vacant, and served from September 19, 1866, to March 3, 1871. He was not a candidate for reelection. While in the Senate, he was chairman of the Committee on the Library (Forty-first Congress).
Cattell was appointed by President Ulysses Grant to be a member of the first United States Civil Service Commission and served two years, resigning to accept the position of United States financial agent in London, serving in 1873 and 1874. He was a member of New Jersey Board of Tax Assessors from 1884 to 1891, and was its president from 1889 to 1891. In 1891, he was appointed a member of the State board of education for a term of three years. Cattell died in Jamestown, New York in 1894 and was interred in Colestown Cemetery, near Merchantville.