Queen Butterfly is serious most of the time, having a low tolerance for anything messy or destructive. Despite being the queen, Queen Butterfly acts as the true ruling monarch of Mewni and always has the well-being of her kingdom in mind, to the point she is unable to express interest in anything else. This often causes her to appear cold towards others. Despite her overbearing strictness, she truly loves and cares for her daughter.
In her youth, Moon used to be just like her daughter, a "Happy go-lucky girl", but after Toffee killed her mother and she inherited the throne, she became serious and mature to protect her kingdom and family.
Queen Butterfly has a slender figure and taller than her husband. She has long pale blue hair with three bangs that resembles her daughter's, often shaped in a heart. She has blue eyes, wears pink lipstick, and purple diamonds on her cheeks. She wears a golden crown with a purple diamond in the center. Her royal outfit includes a light blue and periwinkle gown, the skirt somewhat resembling the shape of a heart, with long blue gloves.
From "Mr. Candle Cares" onward, Queen Butterfly had slightly altered her look; her crown now has a gold diamond-shaped attachment with a purple diamond in the center, from which two strings of pearls curl around the sides of her hair. Her ears are visible, and wears gold diamond-shaped earrings with purple diamonds embedded in them. She now wears purple lipstick.
In her Mewberty form, Moon has large butterfly-like wings and six arms.
- According to Daron Nefcy, Queen Butterfly's first name is Moon.
- In Season Two, Queen Moon receives a redesign to her appearance.
- In "Into the Wand", it is revealed that Queen Butterfly was the one who first defeated Toffee and severed the middle finger on his right hand.