Halloween Costumes for 9 Year Old Girls: 6 Picks by Style
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Halloween costumes for 9 year old girls cover everything from superheroes and classic witches to spooky ghost dresses, dark mermaids, and book characters. This guide covers six different directions so you can match the pick to what she has in mind.
Quick Picks
| Costume | Best For |
|---|---|
| DC Wonder Woman Costume for Girls | A girl who wants the classic Wonder Woman look |
| California Costumes Haunted Beauty | A girl who wants a spooky gothic ghost dress |
| Spooktacular Creations Mermaid Skeleton | A girl who wants a mermaid dress with skeleton detailing |
| Spooktacular Creations Moon Shimmer Witch | A girl who wants a complete witch costume |
| Rubies Harry Potter Gryffindor Robe | A Harry Potter fan who wants the official Hogwarts robe |
| Spooktacular Creations Girls Evil Clown | A girl who wants a colorful but darker jester-style costume |
Comparison Table
| Costume | Style | What’s Included | Best For |
|---|---|---|---|
| Wonder Woman | Superhero/DC | Dress, belt, gauntlets, tiara, boot tops | Girls who want the official Wonder Woman look |
| Haunted Beauty | Gothic/Spooky | Dress, shrug with attached hood, chain | Girls who want a dramatic gothic ghost look |
| Mermaid Skeleton | Dark/Feminine | Dress, cuffs, pearl necklace, hair pin, wand, crown | Girls who want a mermaid dress with skeleton detailing |
| Moon Shimmer Witch | Classic Halloween | Dress, belt with bow detail, hat, broom with ribbons | Girls who want a complete classic witch costume |
| Harry Potter Robe | Book/Movie Character | Officially licensed ankle-length Gryffindor robe with crest | Harry Potter fans who want the official Hogwarts robe |
| Girls Evil Clown | Bold/Creative | Dress, headband, collar, leggings, sleeve decorations | Girls who want a colorful but darker jester-style costume |
DC Wonder Woman Costume for Girls
Why It Stands Out
This officially licensed DC Comics Wonder Woman costume is the Girls Medium (8-10) size. It includes a dress, belt, gauntlets, tiara, and boot tops — five pieces that together create a complete Wonder Woman look without sourcing accessories separately.
Possible Downsides
The listing notes that costume sizing can run smaller than regular apparel, so compare her measurements with the size chart before ordering.
Best For
A girl who wants a classic Wonder Woman superhero costume with all the key accessories included.
California Costumes Girls Haunted Beauty Costume
Why It Stands Out
This set includes a dress, a shrug with an attached hood, and a chain. The attached mesh veil on the hood can be worn over the face or pulled back, giving her two different looks from the same costume. The hooded veil, chain, and gothic dress styling give it a noticeably different look from a traditional ghost costume.
Possible Downsides
The veil covering the face may not be allowed at school events — check school rules before wearing it to any school Halloween activity. Confirm the specific size variant on the Amazon listing before ordering to make sure it fits a 9-year-old.
Best For
A girl who wants something spooky and dramatic without going into full-on horror character territory.
Spooktacular Creations Mermaid Skeleton Costume for Girls
Why It Stands Out
This six-piece set includes a mermaid skeleton dress, cuffs, a pearl necklace, a hair pin, a wand, and a crown. The combination of a mermaid silhouette and skeleton detailing gives it a more unusual look than either a standard mermaid or a standard skeleton costume on its own. Made from 100% polyester.
The included necklace, hair pin, wand, crown, and cuffs give the dress several coordinating accessories without requiring you to source those pieces separately.
Possible Downsides
With six pieces included, there are several smaller accessories to keep track of during trick-or-treating. Confirm the specific size variant on the Amazon listing before ordering to make sure it fits a 9-year-old.
Best For
A girl who wants a mermaid-style dress combined with skeleton detailing and several coordinating accessories.
Spooktacular Creations Moon Shimmer Witch Costume
Why It Stands Out
This four-piece set includes a dress, a belt with a bow detail, a hat, and a broom with five color ribbons. Made from 100% polyester. The pointed hat, broom, and dress keep the classic witch silhouette, while the shimmer detailing gives this version a more elaborate look.
Possible Downsides
The broom is a prop, so check school rules before bringing it to any school event. Confirm the specific size variant on the Amazon listing before ordering to make sure it fits a 9-year-old.
Best For
A girl who wants a classic witch costume with more visual detail than a basic black dress and hat.
Rubies Harry Potter Gryffindor Child’s Costume Robe
Why It Stands Out
This is the officially licensed Rubies Harry Potter Gryffindor robe in the child Medium size. It’s an ankle-length black fleece robe with burgundy lining, an embroidered Gryffindor house crest, an attached hood, and a clasp closure at the neckline. The Gryffindor styling makes this a specific character-world costume rather than a generic wizard robe.
The robe works over whatever she chooses to wear underneath, giving her flexibility in how complete the look is on the night.
Possible Downsides
This is a robe-only item — shirt, pants, tie, wand, and glasses are not included and are available separately. The listing notes costumes run differently from regular apparel, so consult the Rubies size chart before ordering to find the right fit for a 9-year-old.
Best For
A Harry Potter fan who wants to go as a Hogwarts student rather than a generic Halloween character.
Spooktacular Creations Girls Evil Clown Costume
Why It Stands Out
This five-piece set includes a dress, headband, collar, leggings, and sleeve decorations. Made from 100% polyester. The coordinated dress, leggings, collar, headband, and sleeve pieces give the costume a more complete jester-style appearance without requiring anything additional.
Possible Downsides
The look works best with some face makeup, which isn’t included. Without it the costume still reads clearly as a character. Confirm the specific size variant and the exact included pieces on the Amazon listing before ordering to make sure it fits a 9-year-old.
Best For
A girl who wants a colorful but darker clown or jester-style costume.
Frequently Asked Questions
What size should I order for a 9-year-old girl?
Costume sizing varies considerably by brand. Wonder Woman is specifically labelled Girls Medium 8-10, while other brands use different letter and age ranges. Compare her height and measurements with each individual size chart rather than relying on the letter size alone.
Which of these comes with the most pieces?
The mermaid skeleton is the most complete set with six listed pieces including the dress, cuffs, necklace, hair pin, wand, and crown. The Wonder Woman and evil clown costumes each include five pieces. The Harry Potter robe is a single piece worn over her own clothes, with accessories available separately.
Can she wear any of these to school?
Check your school’s specific Halloween policy before choosing. The witch’s broom and the haunted beauty’s face veil are the pieces most likely to need checking. The Wonder Woman costume and Harry Potter robe do not include full-face coverings, although individual school policies still apply.
Can any of these be used for dress-up after Halloween?
Yes. Wonder Woman and the Harry Potter robe are character costumes that can also work for cosplay or dress-up, while the witch, mermaid skeleton, haunted beauty, and clown sets can be reused for costume parties or imaginative play. How much use they get afterward will depend on the child.
Are these warm enough for trick-or-treating on a cold night?
Most of these are dress-style costume pieces. The Harry Potter robe offers good flexibility for layering because the robe is worn over her own clothes. For the dress-style costumes like Wonder Woman and mermaid skeleton, a thin base layer underneath or a jacket between houses is worth planning for on cold nights.
