Phineas and Ferb the Movie: Across the 2nd Dimension is a 2011 American animated science fantasy action-adventure comedy-drama television film based on the American animated TV series Phineas and Ferb. The film premiered on August 5, 2011 in the United States. It was first announced by Jeff "Swampy" Marsh during a January 2010 interview with the Daily Telegraph. The events of the film take place during the third season of Phineas and Ferb. It is the first feature-length film of the Phineas and Ferb series, and the third animated Disney Channel Original Movie, following Kim Possible Movie: So the Drama and The Proud Family Movie.

Phineas and Ferb is an American animated musical-comedy television series created by Dan Povenmire and Jeff "Swampy" Marsh that aired on Disney Channel and Disney XD for four seasons between 2007 and 2015. The series follows stepbrothers Phineas Flynn and Ferb Fletcher during summer vacation. Every day, the boys undertake the construction of a grand project, or embark on a spectacular adventure, to make the most of their time on vacation. This annoys their controlling older sister, Candace, who frequently tries to expose their schemes to her and Phineas's mother. The series follows a standard plot system; running gags occur in every episode.