The Undoing is an American mystery psychological thriller television miniseries based on the 2014 novel You Should Have Known by Jean Hanff Korelitz. It was written and produced by David E. Kelley and directed by Susanne Bier. The miniseries stars Nicole Kidman and Hugh Grant and premiered on HBO on October 25, 2020.

The Undoing was the first HBO show to gain viewership every week over the course of the season, and was the biggest American series to launch on Sky in the United Kingdom, beating the record previously held by Game of Thrones. It was the most-watched show on HBO in 2020. The series received generally positive reviews, with critics praising the performances (particularly Kidman and Grant), cinematography and production design, but some criticizing the writing, pace and characterization.