William Morris Meredith (June 8, 1799–August 17, 1873) was an American lawyer and politician.

Born in Philadelphia, Pennsylvania, he graduated from the University of Pennsylvania in 1812. After he was admitted to the bar 1817, he began practicing law.

He served in the Pennsylvania State Legislature from 1824 to 1828, and was president of the Philadelphia City Council from 1834 until 1849. He was also United States Attorney for the Eastern District of Pennsylvania in 1841.

President Zachary Taylor, wanting a Pennsylvanian Whig for his cabinet, appointed William M. Meredith to be the 19th Secretary of the Treasury. He began his term in office in March 1849. Meredith strongly opposed the free trade legislation passed the year before under Robert J. Walker, the 18th Secretary of the Treasury. He felt that there was a need to protect the American workman, who was subject to competition from poorly paid European labor. Meredith's principal contribution in office was his Annual Report of 1849 in which he set forth an elaborate argument for a protective tariff.

The increase in the public debt due to the Mexican-American War and the acquisition of California gave Meredith additional argument for raising revenue through higher import duties, but no action was taken on the tariff during Meredith's term. He also recommended a revision of the Coast Survey Code , which had not been changed since its implementation in 1806, because the Coast Survey had seen great expansion and improvement with the introduction of steam powered ships. Meredith resigned with the rest of the Presidential Cabinet upon Taylor's death in 1850.

He was the state attorney general of Pennsylvania from 1861 from 1867. In 1870, Meredith served as a member of a commission working out the settlement of the Alabama claims. He died in 1873.

He was a grandnephew to Gouverneur Morris.