List of episodes

Season 2: 2010-2011
Season two contains 26 half episodes and originally aired from October 2010 to mid-2011. Their titles and production codes were revealed on the Frederator Blog.

Season 3: 2011-2012
Season 3 contains 26 half episodes and originally aired on July 2011 to February 2012. Their titles and production codes were revealed on April 6, 2011 on the Frederator Blog.

Season 4: April 2012
Season 4 premiered on April 2, 2012. Episode titles were posted on the Frederator Blog in March 2012.

Writing of the season started on or before May 2011. According to Andy Ristaino, by February 2012, the season had been written, storyboarded and approved. The season will see the premiere of the 100th episode of the series, "The Hard Easy" (previously titled "Prince Huge"). Adam Muto reported that characters not seen since Season 1 will return, with The Earl of Lemongrab, Magic Man, The Lich, Marceline's father and NEPTR being confirmed to return. Adam Muto said that both BMO and Marceline's backstories will be also explored a bit more in this season. The season will feature guest voices by Donald Faison, George Takei, Erik Estrada, Andy Milonakis, Emo Phillips, Bobcat Goldthwait and Susie Essman. There will be two-part episodes in this season. Jeremy Shada also mentioned that Marceline and Ice King will sing together.

Season 5: TBA
In an interview with Charlie Jane Anders, Pendleton Ward revealed that the writers are currently working on Season 5. Jesse Moynihan revealed that as of 30th of July, 2012, works on season 5 storyboards has already ended. He also stated that the pairs working on those were: Jesse Moynihan and Ako Castuera, Cole Sanchez and Rebecca Sugar, Tom Herpich and Steve Wolfhard, Skyler Page and Somvilay Xayaphone with the help of Kent Osborne. , It was stated that the second Fionna and Cake will premiere this season.

Season 6: TBA
One of the show's storyboarders, Jesse Moynihan, has suggested there will be a sixth season. He later said he would be coming back to work on this season in September.

Unproduced episodes
These episodes were planned, and are known from design documents released by Frederator Studios in 2009 during the production of the first season. However, they were not produced for season one, and it is unlikely that they will actually be made into full episodes. According to an old blog post, "Ice King Has a Point" was supposed to be a 27th episode of a 26-episode season, because episode #6 had been scrapped. However, because episode 6 ("What Have You Done?") actually was eventually made, it's likely that "Ice King Has a Point" was either canceled or incorporated into "What Have You Done?"

"Brothers in Insomnia" was originally episode #692-002. However, it was scrapped, and its production number was taken by "Rainy Day Daydream", which was actually one of the last episodes produced for season one.

The Frederator blog also posted notes for an episode that was thought to be titled "You're a Beautiful Dancer". However, Adam Muto later confirmed that "You're a Beautiful Dancer" was just a quote that Finn was saying to Jake and was never meant to be an episode title. He stated that the page in question only contained random story ideas that were never fully developed into episodes.

Adam Muto has confirmed "Jakesuit" eventually worked its way into "The Silent King", which may give hints about the plot outline of "Jakesuit".