"Unmasked" is the season finale and the twenty-fifth episode of the second season of Pretty Little Liars, which premiered on ABC Family on March 19, 2012. The forty-seventh episode overall, it was directed by Lesli Linka Glatter and written by series creator and showrunner I. Marlene King. The episode yielded 3.69 million viewers and a 1.6 demo rating, an increase from the previous episode. It received widespread acclaim from critics, with many noting the satisfying reveal and climactic final scenes, and is often noted as one of the best episodes of the series. In particular, the performances of Janel Parrish and Shay Mitchell received critical praise.

The second season of Pretty Little Liars, based on the books of the same name by Sara Shepard, premiered on June 14, 2011, and concluded on March 19, 2012, on ABC Family. On January 10, 2011, ABC Family renewed the series for a second season. The season premiere brought in 3.68 million viewers, which was higher than the season 1 premiere. The Halloween special aired on October 19, 2011, drawing 2.5 million total viewers. The second half of season 2 premiered on January 2, 2012.