Omo (오모) — which can be interchangeably used with “omona” (어머나) — is a Korean interjection which means something akin to the English expressions “Oh my!”, “Oh my gosh!” or “Oh my god!”, denoting surprise. Its use is closely related to “aigoo” (아이구), however omo appears to have a more positive connotation according to some sources.

It is notable by its frequent use in Korean dramas. As defined on Dramafever, omo is “the ‘OMG’ of Korea. One usually uses this term when wanting to make a current situation even more dramatic. This term is best used when you find out something extremely surprising and shocking. If you really want to sound like you're shocked use multiple ‘omo’" back to back really fast!”

Not to be confused with the brand of laundry detergent made by Unilever.