Phineas and Ferb is an American animated musical-comedy television series created by Dan Povenmire and Jeff "Swampy" Marsh for Disney Channel and Disney XD. The series originally aired on the networks for four seasons between 2007 and 2015, and is scheduled to return for the first of two additional seasons in 2025. The series follows stepbrothers Phineas Flynn and Ferb Fletcher, who construct a grand project or embark on an adventure to make the most of their time on summer vacation, which annoys Phineas' older sister Candace Flynn. Candace's attempts to expose their schemes to her mother always fail due to the fights between Dr. Heinz Doofenshmirtz and the boys' secret agent pet Perry the Platypus destroying their work. The series follows a standard plot system; running gags occur every episode.

Povenmire and Marsh conceived the characters while working together on animated programs The Simpsons and Rocko's Modern Life in the 1990s, and were inspired by the summers of their own childhoods. They developed the series together and pitched it to networks for 16 years before successfully selling it to The Walt Disney Company. Phineas and Ferb is produced by Disney Television Animation, and was originally broadcast as a one-episode preview on August 17, 2007, following the premiere of the made-for-television film High School Musical 2. It again previewed on September 28, 2007, and officially premiered on Disney Channel on February 1, 2008. The series originally concluded on June 12, 2015, before two new seasons were ordered in January 2023, with the fifth season scheduled to premiere on Disney Channel and Disney XD on June 5, 2025, and on Disney+ the following day.

Phineas and Ferb is one of Disney Channel's most successful animated franchises. It received high viewership in the United States on cable television and influenced the development of merchandise, a live tour, spin-offs, and movies. A made-for-television film, Phineas and Ferb the Movie: Across the 2nd Dimension, aired in 2011, while a follow-up titled Phineas and Ferb the Movie: Candace Against the Universe was released on Disney+ in 2020. Critics praised the writing and humor of the show, citing its appeal to a wide range of ages. Others criticized its lack of originality and formulaic approach. The series won a Daytime Emmy Award in 2010 for Outstanding Writing in Animation and several Primetime Emmy Awards for Outstanding Individual Achievement in Animation.