In the United States, prohibition was a nationwide constitutional law that strictly prohibited the production, importation, transportation, and sale of alcoholic beverages from 1920 to 1933.Prohibitionists first attempted to end the trade in alcoholic drinks during the 19th century. Led by pietistic Protestants, they aimed to heal what they saw as an ill society beset by alcohol-related problems such as alcoholism, family violence, and saloon-based political corruption. Many communities introduced alcohol bans in the late 19th and early 20th centuries, and enforcement of these new prohibition laws became a topic of debate. Prohibition supporters, called "drys", presented it as a battle for public morals and health. The movement was taken up by progressives in the Prohibition, Democratic and Republican parties, and gained a national grassroots base through the Woman's Christian Temperance Union. After 1900, it was coordinated by the Anti-Saloon League. Opposition from the beer industry mobilized "wet" supporters from the wealthy Roman Catholic and German Lutheran communities, but the influence of these groups receded from 1917 following the entry of the U.S. into the First World War against Germany.

The alcohol industry was curtailed by a succession of state legislatures, and finally ended nationwide under the Eighteenth Amendment to the United States Constitution, ratified on January 16, 1919, which passed "with a 68 percent supermajority in the House of Representatives and 76 percent support in the Senate" as well as ratification by 46 out of 48 states. Enabling legislation, known as the Volstead Act, set down the rules for enforcing the federal ban and defined the types of alcoholic beverages that were prohibited. Not all alcohol was banned; for example, religious use of wine was permitted. Private ownership and consumption of alcohol were not made illegal under federal law, but local laws were stricter in many areas, some states banning possession outright.

Following the ban, criminal gangs gained control of the beer and liquor supply in many cities. By the late 1920s, a new opposition to Prohibition emerged nationwide. Critics attacked the policy as causing crime, lowering local revenues, and imposing "rural" Protestant religious values on "urban" America. Prohibition ended with the ratification of the Twenty-first Amendment, which repealed the Eighteenth Amendment on December 5, 1933, though prohibition continued in some states. To date, this is the only time in American history in which a constitutional amendment was passed for the purpose of repealing another.

Some research indicates that alcohol consumption declined substantially due to Prohibition. Other research indicates that Prohibition did not reduce alcohol consumption in the long-term. Rates of liver cirrhosis, alcoholic psychosis, and infant mortality also declined. Prohibition's effect on rates of crime and violence is disputed. Prohibition lost supporters every year it was in action, and lowered government tax revenues at a critical time before and during the Great Depression.

The Eighteenth Amendment (Amendment XVIII) of the United States Constitution established the prohibition of alcohol in the United States. The amendment was proposed by Congress on December 18, 1917, and was ratified by the requisite number of states on January 16, 1919. The Eighteenth Amendment was repealed by the Twenty-first Amendment on December 5, 1933. It is the only amendment to be repealed.

The Eighteenth Amendment was the product of decades of efforts by the temperance movement, which held that a ban on the sale of alcohol would ameliorate poverty and other societal issues. The Eighteenth Amendment declared the production, transport, and sale of intoxicating liquors illegal, though it did not outlaw the actual consumption of alcohol. Shortly after the amendment was ratified, Congress passed the Volstead Act to provide for the federal enforcement of Prohibition. The Volstead Act declared that liquor, wine, and beer all qualified as intoxicating liquors and were therefore prohibited. Under the terms of the Eighteenth Amendment, Prohibition began on January 17, 1920, one year after the amendment was ratified.

Although the Eighteenth Amendment led to a decline in alcohol consumption in the United States, nationwide enforcement of Prohibition proved difficult, particularly in cities. Rum-running (bootlegging) and speakeasies became popular in many areas. Public sentiment began to turn against Prohibition during the 1920s, and 1932 Democratic presidential nominee Franklin D. Roosevelt called for its repeal. The Twenty-first Amendment finally did repeal the Eighteenth in 1933, making the Eighteenth Amendment the only one so far to be repealed in its entirety.