Princess Bonnibel Bubblegum (also called Bonnie or PB, occasionally Peebles or P-bubs) is a fictional character in the American animated television series Adventure Time and resulting franchise, created by Pendleton Ward. She is voiced by Hynden Walch.

Princess Bonnibel Bubblegum is the ruler of the Candy Kingdom, which other "Candy People" inhabit. She is good friends with the series' protagonists Finn the Human and Jake the Dog, first appearing alongside them in Ward's 2008 pilot. Princess Bubblegum is the living incarnation of the Candy Elemental, formed from a massive, blob-like, pink gum biomass known as the "Mother Gum" in the years following the Mushroom War. In addition to ruling the Candy Kingdom, Princess Bubblegum is also a brilliant scientist, dedicating her life to improving the existence of her kingdom's citizens, regularly making scientific breakthroughs in her lab. Princess Bubblegum's sexual orientation has not been officially confirmed, however, in the series finale of Adventure Time, "Come Along with Me", she and Marceline the Vampire Queen shared an on-screen kiss, confirming their romantic relationship.

A gender-swapped version of Princess Bubblegum called Prince Gumball appeared in the third-season episode "Fionna and Cake".

Bubblegum is typically very kind and compassionate, having a strong sense of justice, sometimes despairing of her responsibilities. She is brilliant, creating the Candy People and various devices, including a miniature time machine. She is fluent in German and Korean, using the latter language to communicate with her friend Lady Rainicorn. Bubblegum is skeptical of magic, refusing to acknowledge it as anything other than “scientific principles presented like mystical hoodoo.”

Bubblegum's leadership is paternalistic due to her subjects being naive and childlike. She believes that, without a guiding hand, they'd quickly destroy themselves. Bubblegum is highly protective of the Candy People and cares deeply for their safety, but is secretly strained by the pressures of ruling and expresses a desire for freedom from responsibility for her actions. Following a near-death experience at the end of the second season, she starts to isolate herself and becomes overprotective of the Candy People, even exhibiting authoritarian tendencies temporarily in the fifth season such as installing multiple cameras in the kingdom and implanting tracking chips in every citizen. At the end of the sixth season, Bubblegum is deposed as ruler following an election, where she realizes she has made the Candy People too unintelligent. Following the miniseries Stakes, Bubblegum is reinstated as ruler and becomes less overprotective.

Bubblegum has light pink skin and long magenta "hair," which is made of bubblegum. Her usual outfit is a puffy-sleeved pink gown with purple trim, and her golden circlet crown with a turquoise jewel. Among many other outfits, she often wears a lab coat and glasses during science experiments. Additionally, Princess Bubblegum's crown and matching earrings have magic properties which protect her from the Lich's mind-controlling powers as seen in the episode "Mortal Folly".

Being made of candy, Bubblegum can deform and reform her biomass, through which she can regain lost body parts and fluctuate her biological age. She usually appears bodily to be 18 years old, though her actual age is estimated to be 827; she was born hundreds of years before the events of the series from a gum-like ooze, the "Mother Gum." Bubblegum temporarily becomes 13 years old after the second season finale episode "Mortal Recoil" due to losing too much biomass after being attacked by the Lich, where she is voiced by Isabella Acres until the end of "Too Young" where she is restored to her 18 year old form.

In the seventh season, Bubblegum discovers that she is an incarnation of the "Candy Elemental," the living embodiment of candy as one of the Adventure Time universe's four classical elements (fire, ice, candy, and slime). Like the Elemental, she can materialize various quantities of candy through her hands and communicate with past incarnations of the Elemental. When Bubblegum's elemental powers consume her in the miniseries Elements, she becomes psychically connected to all candy in the universe. She can transform others into candy, upon which they lose the memory of their life before their transformation.