Once Upon a Time in Wonderland is an American fantasy–drama series that aired on ABC from October 10, 2013 to April 3, 2014. It was created by Edward Kitsis, Adam Horowitz, Zack Estrin, and Jane Espenson for ABC Studios. The program is a spin-off of the prior ABC series Once Upon a Time and aired on ABC at 8:00 pm Eastern/7:00 pm Central on Thursday nights in the 2013–14 television season beginning October 10, 2013.

The series is based around the Lewis Carroll novels Alice’s Adventures in Wonderland and Through the Looking-Glass but with a different twist from the other adaptations and takes place in the same universe as Once Upon a Time in present-day Wonderland, with flashbacks to pre-Dark Curse Wonderland. As such, it follows the same setting as the parent series, including the use of Disney- and Lost-related allusions. In addition, the series features occasional crossover events with Once Upon a Time that involves connections with the characters that are trapped in Storybrooke, Maine.

The series received mixed to positive reviews from critics who praised its cast, visuals, and narrative, but criticized the muddled plot. On March 27, 2014, it was revealed that the series would be ending after one season, with the series finale airing on April 3, 2014. On April 1, 2014, it was reported that Michael Socha was in talks to reprise his role as Will Scarlet/Knave of Hearts as a series regular in the fourth season of Once Upon a Time. On April 20, 2014, it was confirmed that Michael Socha would become a regular for the fourth season of the parent series.