Princess Star Butterfly is the main protagonist and the heroine of Star vs. the Forces of Evil. She is a teenage princess of the Kingdom of Mewni from another dimension sent to Earth by her royal parents after an altercation with a couple of monsters. She currently lives with her Earthly hosts, the Diaz family.
Star is energetic and friendly so she loves having fun, and she usually has an optimistic outlook on life. She loves to help others and whenever she sees that someone is upset, she does her best to cheer them up. Strangers, in her eyes, are just friends she hasn't met yet, and she feels bad if she hurts someone's feelings, whether intentionally or not. Star has a happy-go-lucky attitude and always puts a smile on everyone's faces. She also works very hard towards her goals, so much that she'll sometimes end up greatly sleep-deprived.
Owing to her rather sheltered upbringing, Star's optimism and enthusiasm can border on recklessness, to the point of endangering people around her with her madcap antics. She has rather simplistic views on concepts such as leadership and responsibility, believing that prioritizing fun above all else matters the most. All this, coupled with her lack of understanding of Earth customs, often puts her and Marco in strange, dangerous situations. While rarely ever angry, she does express annoyance to people who don't take her seriously or give her the attention she wants. Although she treats her friends kindly and rarely holds grudges against them, she's usually brutal towards her enemies.
She sometimes chews on the top of the wand, in somewhat of a tic.
She has coulrophobia (a fear of clowns) but by "Royal Pain," she seems to have gotten over it, since there was a clown creature in her room, and she didn't seem to mind it.
In "Sleep Spells", it's revealed that she has issues with her mother.
Star is a girl of medium height. She has long blonde hair down to her knees, and posh pearl pink hearts as cheeks and has big blue eyes. Usually, she wears a red hairband with devil horns and lets her hair down, though she sometimes uses her magic wand to change into other hairstyles.
While Star has many different outfits, she mainly wears three recurring outfits:
- She has a sea green dress with a white collar, white lace on the sleeves and bottom, and a cute light purple squid design on the front. She also wears pink and orange stockings, dark magenta boots with a rhino design, and a little yellow star-shaped side bag with a face.
- She has a turquiose, sleeveless dress with four colorful stripes on the chest, white lace on the bottom, and a white bear face on her left side towards the bottom. She also wears light seagreen and bluish green-striped stockings, pink boots with white bunny faces and dark pink bottoms, and a silver bracelet with spikes.
- She has a sky blue sleeveless short dress with a tied string at the neckline. Around the waist, the dress has a peach-colored line, and a red line that is slanted towards the right. She also wears a little gray cloud-shaped bag with a face, striped blue stockings that are dark blue at the top and becoming lighter with each lower stripe, light blue sneakers with white tips, and fuzzy light blue legwarmers.
- She is inspired by Jenny Wakeman from My Life as a Teenage Robot and Serena Tsukino from Sailor Moon.
- Star Butterfly shares similarities to Starfire from Teen Titans:
- Both are Cheerful.
- Both are Princesses.
- Both have long hair.
- Both have pets, Star has Laser Puppies, Starfire has Silkie.
- Both have powers.
- The differences between Star Butterfly and Starfire.
- Star Butterfly is a Mewmans princess and Starfire is a alien princess.
- Star butterfly has magic wand and Starfire has Laser eyes, Flight and Super Strength.
- Star's appearance resembles to that of Pacifica Northwest from Gravity Falls. In fact, Star can be viewed as a glimpse of who Pacifica might have been had the latter was raised in actual loving and caring rather than getting abused and forced.
- Mabel Pines (Gravity Falls)
- Lightbulb (Inanimate Insanity)
- Steven Universe and Connie Maheswaran (Steven Universe)
- Sandy Cheeks (Spongebob Squarepants)
- Jenny Wakeman (My Life as a Teenage Robot)
- Serena (Pokemon)
- Starfire (Teen Titans)
- Usagi Tsukino (Sailor Moon)
- Mimi Tachikawa (Digimon)
- Amy Rose (Sonic the Hedgehog)
- Kuki Sanban (Codename: Kids Next Door)
- Arale Norimaki (Dr. Slump)
- Emma Goodall (Power Rangers Megaforce)
- Twilight Sparkle and Pinkie Pie (My Little Pony Friendship is Magic)
- Lucy Wilde (Despicable Me 2)
- Kagura (Gintama)
- Leni Loud (The Loud House)
- Joy and Riley Andersen (Inside Out)
- Anna (Frozen)
- Ami Onuki (HiHi Puffy AmiYumi)
- Judy Hopps (Zootopia)
- Honey Lemon (Big Hero 6)
- Rapunzel (Tangled)