The Tariff Act of 1930 (codified at 19 U.S.C. ch. 4), commonly known as the Hawley–Smoot Tariff or Smoot–Hawley Tariff, was a law that implemented protectionist trade policies in the United States. Sponsored by Senator Reed Smoot and Representative Willis C. Hawley, it was signed by President Herbert Hoover on June 17, 1930. The act raised US tariffs on over 20,000 imported goods.

The tariffs under the act, excluding duty-free imports (see Tariff levels below), were the second highest in United States history, exceeded by only the Tariff of 1828. The Act prompted retaliatory tariffs by affected states against the United States. The Act and tariffs imposed by America's trading partners in retaliation were major factors of the reduction of American exports and imports by 67% during the Depression. Economists and economic historians have a consensus view that the passage of the Smoot–Hawley Tariff worsened the effects of the Great Depression.