Timothy John Campbell (January 8, 1840 – April 7, 1904) was an American lawyer and politician from New York.
Born in County Cavan, Ireland, he emigrated to New York City.
He was a member of the New York State Assembly (New York Co., 6th D.) in 1868, 1869, 1870, 1871, 1872, 1873, 1875 and 1883.
He was a member of the New York State Senate (6th D.) in 1884 and 1885.
He was elected as a Democrat to the 49th United States Congress, to fill the vacancy caused by the resignation of Samuel S. Cox, was re-elected to the 50th, and was elected again to the 52nd and 53rd United States Congresses, holding office from November 3, 1885, to March 3, 1889; and from March 4, 1891, to March 3, 1895.
Campbell earned a touch of immortality of an attributed nature. He is reported to have said to President Grover Cleveland, upon Cleveland's saying he would not support a bill on the grounds that the bill was unconstitutional, "What's the Constitution between friends?" (Bartlett's Familiar Quotations, 16th ed.)