Marriner Stoddard Eccles (September 9, 1890 – December 18, 1977) was an American economist and banker who served as the 7th chairman of the Federal Reserve from 1934 to 1948. After his term as chairman, Eccles continued to serve as a member of the Federal Reserve Board of Governors until 1951.

Eccles was known during his lifetime chiefly as having been the Chairman of the Federal Reserve under President Franklin D. Roosevelt. He has been remembered for having anticipated and supporting the theories of John Maynard Keynes relative to "inadequate aggregate spending" in the economy which appeared during his tenure. As Eccles wrote in his memoir Beckoning Frontiers (1951):

As mass production has to be accompanied by mass consumption, mass consumption, in turn, implies a distribution of wealth ... to provide men with buying power. ... Instead of achieving that kind of distribution, a giant suction pump had by 1929–1930 drawn into a few hands an increasing portion of currently produced wealth. ... The other fellows could stay in the game only by borrowing. When their credit ran out, the game stopped.