Costumes That Start with O

Costumes That Start with O

Ever found yourself frantically brainstorming costume ideas for a themed party, a school event, or Halloween only to realize the theme is “Letters of the Alphabet”? And your assigned letter? O!

Don’t worry, been there, panicked about that, and came out on the other side with a list of fun, creative, and budget-friendly costumes. Let's chat about all the fantastic “O” options that’ll have you, your kids, or even your partner looking oh-so-original.

Fun Letter O Costume Ideas

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Octopus

Let’s kick things off with the classic underwater wonder, the octopus. This one’s great for all ages!

  • How to make it simple: Grab a sweatshirt, some matching tights or leggings, and stuff eight socks or tights with pillow stuffing for the arms. Sew or safety pin the arms around the waist.
  • Extra fun: Add googly eyes to a beanie or wear a plastic headband with pipe cleaners for antennae. Bonus points if you add suction cups (like stick-on hooks or painted bottle caps) to the tentacles.

Ostrich

Who doesn’t love a costume that’s totally unique and hilarious? 

    • DIY version: Use a fluffy tutu or feather boa around the waist for the ostrich body. Then, attach faux ostrich legs (stuffed leggings with shoes) to your own legs for a riding-on-an-ostrich look.
    • Pre-made option: Amazon or costume shops often have inflatable ostrich costumes if you’re short on time.

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Orange

Keeping it simple, this one’s perfect for kids who want minimal fuss.

  • The outfit: Wear all orange and go as, well, an orange! Add a green stem hat for flair.
  • Pro-level twist: Be a glass of orange juice! Add a straw made from a pool noodle and a cutout “OJ” label pinned to the shirt.
  • Why I love this: It’s quick, affordable, and perfect for last-minute prep.

Olympian

Channel those sporty vibes with an Olympian costume. It’s a hit for kids who live in their sneakers anyway.

  • What you’ll need: A tracksuit or athletic gear, a DIY gold medal (made from cardboard and spray paint), and a water bottle to complete the look.
  • Mom spin: If you’re dressing up as a family, each person can represent a different Olympic sport. Picture one kid as a gymnast, another as a swimmer, and mom or dad as the coach!

Ogre

Feeling a bit “Shrek-tastic”? Let’s go full ogre mode!

    • Easy option: Green face paint, a plaid shirt, and a pair of brown pants. Add some DIY ogre ears (felt or foam on a headband).
    • Family idea: Go as the Shrek crew! One kid as Fiona, another as Donkey, and the rest can pick their fairy-tale faves.
    • Laugh factor: This is one of those costumes that screams, “We’re here for fun, not perfection.”

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Opera Singer

Got a little diva in the house? This costume lets them shine!

  • How to create it: A fancy dress or tuxedo, dramatic makeup, and some oversized jewelry. Add a microphone prop or music sheet for extra flair.
  • Fun twist: Wear a Viking-style helmet and belt to play up the stereotype of the dramatic opera singer.
  • Pro tip: Teach your little one (or yourself) to belt out a mock aria for full effect.

Old-Timey Person

Step back in time with an “old-fashioned” costume that’s both nostalgic and adorable.

  • Ideas to explore: Think 1920s flapper, 1950s greaser, or a Victorian-era ensemble.
  • For a laugh: Dress up as an “old man” or “old lady” complete with gray hair (spray-on dye or a wig), a cane, and glasses.
  • Why it’s great: It’s versatile, and you can often raid your closet or thrift store for everything you need.

Oreo Cookie

For the sweet tooth in all of us, you can’t go wrong with an Oreo costume!

  • DIY it: Use black foam board or fabric to make two “cookie” discs, and sandwich a white foam circle in the middle for the filling. Attach straps so you can wear it like a sandwich board.
  • Cutest idea: Dress up as a Double Stuf Oreo with a buddy, one cookie for each of you!
  • Snack bonus: Hand out mini Oreos while you’re out and about. Instant crowd-pleaser.

Officer

Calling all crime fighters! A police officer costume is a timeless option.

  • How to assemble: Navy or black pants, a matching shirt, and a badge (realistic toy ones work perfectly). Don’t forget the hat and handcuffs!
  • Family version: One person as an officer, another as a robber, and maybe even a jailbird toddler for giggles.
  • What I love: It’s super recognizable, and kids love the chance to “patrol” the party.

Optimus Prime

For the Transformer fans, this one’s a showstopper.

  • DIY hack: Use cardboard boxes painted in blue and red to create the iconic truck-turned-robot look.
  • Shortcut: Pre-made costumes are widely available if DIY isn’t your thing.
  • Kid favorite: They’ll love making robotic sound effects while they strut their stuff.

Orchestra Conductor

Fancy and fabulous, an orchestra conductor is a classy choice.

  • Put it together: Wear a tuxedo or black suit, carry a baton (or a wooden spoon—it works!), and add a sheet of music.
  • Fun twist: Conduct an imaginary symphony while you walk around, it’s sure to get laughs.
  • Why it works: It’s simple yet creative, and perfect for anyone who loves music.

Oompa Loompa

From Charlie and the Chocolate Factory, these little guys are unforgettable!

  • What you need: White pants or overalls, a brown shirt, green hair (wig or spray), and orange face paint.
  • Group idea: Go as Willy Wonka and the Oompa Loompas for a coordinated family look.
  • Warning: Prepare for the endless singing of “Oompa Loompa, do-ba-dee-do.”

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Owl

Whoooo’s ready to look adorable? Owls are a hoot!

  • DIY magic: Cut out “feathers” from felt in various shades of brown, white, and tan, and glue them to a plain shirt. Add a felt mask for the face and a pair of wings made from fabric or cardboard.
  • Why it’s awesome: It’s great for little ones, and it can be as simple or elaborate as you like.

Orca (Killer Whale)

Perfect for ocean lovers or anyone who wants a sleek, easy costume.

  • DIY version: Black and white clothing with felt cutouts to mimic the whale’s markings. Add a black hood or beanie for the head.
  • Pre-made option: You can find adorable orca onesies online that double as cozy pajamas.
  • Kid-friendly: It’s fun and unique without being too complicated.

Outlaw

Unleash your inner rebel with a Wild West outlaw costume.

  • The basics: Jeans, boots, a plaid shirt, and a cowboy hat. Add a bandana around your neck or face for that classic outlaw vibe.
  • Extra flair: Create a “Wanted” poster to carry around with your photo or name on it.
  • Why it’s cool: It’s rugged, fun, and easy to throw together with stuff you might already have.

Optician

Here’s a clever and simple one that works for adults or older kids.

  • The look: A white lab coat, glasses (real or fake), and an eye chart as a prop.
  • Funny twist: Carry around oversized glasses or wear a comically large pair.
  • Why it works: It’s straightforward and clever without needing too much effort.

Oxford Professor

Get academic with this classy costume.

  • Wardrobe staples: Tweed blazer, a bow tie or scarf, and some round glasses. Carry a stack of books to complete the look.
  • Optional prop: Add a pipe (fake, of course) for an old-school professor vibe.

Oil Tycoon

Dripping with humor and sophistication, this costume’s a real gusher!

  • What to wear: A suit, cowboy hat, and bolo tie. Carry a toy oil rig or bucket labeled "Oil."
  • Why it’s unique: It’s funny, dramatic, and perfect for a conversation starter.

One-Eyed Monster

This costume is perfect for fans of quirky and colorful characters.

    • DIY it: Wear all green, and create one large eye on a headband or mask. Add goofy features like horns or teeth for extra fun.
    • Why it’s awesome: It’s kid-friendly, silly, and super simple.

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Costumes beginning with “O” don’t have to be overwhelming or ordinary. Whether you’re throwing something together last minute or going full Pinterest-level creative, there’s something here for everyone in the family. 

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