Hugh McCulloch (December 7, 1808 - May 24, 1895) was an American statesman who served two non-consecutive terms as U.S. Treasury Secretary.

Born at Kennebunk, Maine, he was educated at Bowdoin College, studied law in Boston, and in 1833 began practicing law at Fort Wayne, Indiana. He was cashier and manager of the Fort Wayne branch of the old state bank of Indiana from 1835 to 1857, and president of the new state bank from 1857 to 1863. Notwithstanding his early opposition to the National Banking Act of 1862 , he was selected by Salmon P. Chase to be the first Comptroller of the Currency in 1863. During McCulloch's 22 months in office, 868 national banks were chartered and no failures occurred. As the first Comptroller, McCulloch recommended major changes in the banking law and the resulting National Banking Act of 1864 remains the foundation of the national banking system.

His work was so successful (largely due to his influence with existing state banks) that he was appointed 27th Secretary of the Treasury by President Abraham Lincoln in 1865, and continued to serve in the Presidential Cabinet of Andrew Johnson until the close of his administration in 1869.

Immediately confronted with inflation caused by the government's wartime issue of greenbacks, he recommended their retirement and a return to the gold standard. In McCulloch's first annual report, issued on December 4, 1865, he strongly urged the retirement of the legal tenders or greenbacks as a preliminary to the resumption of specie payments. However this would have reduced the supply of currency and was unpopular during the period of postwar reconstruction and westward expansion.

In accordance with this suggestion an act was passed, on March 12, 1866, authorizing the retirement of not more than $10,000,000 in six months and not more than $4,000,000 per month thereafter. This act met with strong opposition and was repealed on the February 4, 1868, after only $48,000,000 had been retired. The battle over its revival raged for the next fifty years. McCulloch was also disappointed by the decision of the United States Supreme Court upholding the constitutionality of the legal tenders.

During his tenure, McCulloch maintained a policy of reducing the federal war debt and the careful reintroduction of federal taxation in the South.

Soon after the close of his term of office McCulloch went to England, and spent six years (1870-1876) as a member of the banking firm of Jay Cooke, McCulloch & Co.

From October 1884 until the close of President Chester Arthur's term of office in March 1885 he was again secretary of the treasury, the 36th in the line. During his six months in office at that time, he continued his fight for currency backed by gold, warning that the coinage of silver, used by then as backing for currency, should be halted.

He died at his home Holly Hill near in Prince George's County, Maryland near Washington, D.C. in 1895 and is buried in Rock Creek Cemetery in D.C.

The chief authority for the life of McCulloch is his own book, Men and Measures of Half a Century (New York, 1888).

|- style="text-align: center;" | width="30%" |Preceded by:
Walter Q. Gresham | width="40%" style="text-align: center;" |United States Secretary of the Treasury
1884–1885 | width="30%" |Succeeded by:
Daniel Manning