In the United States, the term hyphenated American refers to the use of a hyphen (in some styles of writing) between the name of an ethnicity and the word American in compound nouns, e.g., as in Irish-American. Calling a person a "hyphenated American" was used as an insult alleging divided political or national loyalties, especially in times of war. It was used from 1890 to 1920 to disparage Americans who were of foreign birth or ancestry and who displayed an affection for their ancestral language and culture. It was most commonly used during World War I against Americans from White ethnic backgrounds who favored United States neutrality during the ongoing conflict or who opposed the idea of an American alliance with the British Empire and the creation of what is now called the Special Relationship, even for purely political reasons.

In this context, the term "the hyphen" was a metonymical reference to this kind of ethnicity descriptor, and "dropping the hyphen" referred to full integration into the American identity.

Presidents Theodore Roosevelt and Woodrow Wilson were outspoken anti-hyphenates. Contemporary studies and debates refer to Hyphenated-American identities to discuss issues such as multiculturalism and immigration in the U.S. political climate; however, the term "hyphen" is rarely used per the recommendation of modern style guides.