Princess Bonnibel, "Bonnibel Bubblegum" or "Bonnie" Bubblegum (often called PB and on occasion Peebles, P-Bubs, or other nicknames) is a main character and the most recurring Princess on the series Adventure Time, and first appeared in the animated short. She is a scientist, inventor, and the ruler over the Candy Kingdom. She was outvoted by the King of Ooo in "Hot Diggity Doom" and later quit, until a rebellion against King of Ooo allowed her to reclaim the throne in "The Dark Cloud." According to the events in "Princess Day," during her first rule over the kingdom, she was considered a registered princess. In "The Dark Cloud" she regained her status as princess near the end, as seen in the song "Everything Stays."

Bubblegum takes on the physical appearance referenced as being in her late teens by three people. Lemongrab and Finn referred to her usual form preceding her de-aging as being 18. Later, in "The Vault," Finn's comment "PB, you're like a bazillion years old! You're not freaking 19, what the heck?!" appears to a reply of her claiming to be 19 offscreen.

Her age appearance can change with a loss of candy biomass: she takes on a 13-year old appearance due to the events of "Mortal Recoil," but returns to the age of 18 due to gaining new biomass in "Too Young." However, she also states in "Goliad" that she knows that she is not going to live forever, implying that although her life is long, it is limited.