Uh-oh! is a ubiquitous interjection or expression of dismay in the English language, generally uttered in anticipation, rather than after something bad has happened. The speaker often gives vent to the expression immediately upon learning or perceiving of something that presages disaster. It is an expression usually acquired very early in life, typically as early as the toddler stage. It is one of few words or phrases in English commonly pronounced with a glottal stop.
It has been used several times in the popular children's show Teletubbies.