Eh ( or ) or Ay (New Zealand English) is a spoken interjection used in many varieties of English. The oldest Oxford English Dictionary defines eh as an "interjectional interrogative particle often inviting assent to the sentiment expressed." Today, while eh has many different uses, especially within a Canadian context, it is most popularly used in a manner similar in meaning to "Excuse me?", "Please repeat that", or "Huh?". It is also commonly used as an alternative to the question tag right?, i.e., method for inciting a reply, as in "Don't you think?", "You agree with me, right?", as in, "It's nice here, eh?" (instead of "It's nice here, right?"). In the Americas, it is most commonly associated with Canada and Canadian English, though it is also common in England, Scotland, and New Zealand. It is also known in some American regions bordering Canada, including the area stretching from northern Wisconsin up to Michigan's Upper Peninsula. Similar interjections exist in many other languages, such as Azerbaijani and Italian.

The spelling of this sound in English is quite different from the common usage of these letters. The vowel is sounded in one of the continental manners (as in French, only missing the apostrophe), and the letter h is used to indicate it is long, as though the origin of the spelling were German.

While evidence suggests that eh initially may have been considered an onomatopoeic sound, the earliest uses of eh found so far date back to Early Modern English in 1662. In 1707, it was first used in a play, functioning “to create or confirm agreement.” Later, in 1773, its earliest quotation, s.v. “eh” was in a play by Irish playwright Oliver Goldsmith.