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Best Costumes Starting with O for 2024

If you’re looking for some great costumes starting with O then you’ve come to the right place. We’ve got heaps of fun costumes that start with O for everyone. We have costumes beginning with O for adults, kids, babies, pets and couples.

You’ll find lots of fun ideas for Halloween costumes beginning with O that are also perfect for other dress up occasions such as costume parties, book week and dress up starting with O parties.

Whether you’re looking to buy or DIY a fun costume – from Octopus costumes to Oompa Loompa costumes – we’ve got you covered.

costumes starting with o

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Costumes Starting with O

We wanted to compile all the most fun and unique costumes that start with O in the one place. If you are invited to an O themed party –  or dress up as something that starts with the first letter of your name – definitely scroll down for all the photos. Or if you just wanted some quick, fun inspiration for a costume for Halloween – we can help. Whether you decide to buy or DIY a costume – see the fun ideas below.

All of the costumes pictured (and many more that couldn’t fit on the page) are available to be purchased right here.  If you see an adults costume you like, you’ll find that there are often similar costumes for kids and pets as well in the link below each category.

We have costumes that will make you stand out in the crowd – as well as low-key costumes such as a t-shirt or a costume hat/headband. At the very least you could do an easy costume with the letter O t-shirt pictured below.

Letter O Name Initial Varsity Alphabet Monogram T-Shirt
Letter O T Shirt

Costumes that Start with O

In this article you’ll find:

  • Womens Costumes
  • Mens Costumes
  • Plus Size Costumes
  • Baby Costumes
  • Pets Costumes
  • Couples Costumes

All the costumes pictured in this article are available to purchase and as well as many others that aren’t pictured in this article. You can find all the costume ideas beginning with O that are available to purchase right here.

We have the fancy dress beginning with O list divided into categories such as characters, things, animals, celebrities, food and more. Scroll down to see all the amazing costume ideas that you probably haven’t thought of.

Things Beginning with O Fancy Dress

  • Ocean
RAISEVERN Girls Dresses Shark Ocean Octopus Pattern Sleeveless Casual Dress Summer Party Swing Sundress for Little Kids Birthday Size 4 5 Years Old
Ocean Dress


  • Oven
Bun in the Oven Halloween Costume - Funny Maternity Outfits for Pregnant Women
Oven Costume
  • Oasis
  • Olympics
  • Organizer
  • Organ
  • Oxygen
  • Oak Tree
  • Orchard
  • One

Find all the things costumes starting with O right here.

Characters Starting with O Costumes

  • Obi Wan Kenobi
STAR WARS Adult Jedi Obi-Wan Kenobi Costume, Mens Halloween Costume - Officially Licensed Large
Obi Wan Kenobi Costume
  • Olaf
Disguise Adult Olaf Costume X-Large White
Olaf Costume
  • Oscar the Grouch
Disguise mens Oscar the Grouch Adult Sized Costumes, Green, X-Large 42-46 US
Oscar the Grouch Costume
  • Olive Oyl
FunWorld Women's Olive Oyl Costume Size 10-14, Black, M/L 10-14
Olive Oyl Costume
  • Optimus Prime
Disguise Men's Optimus Prime Movie Deluxe Adult Costume, Blue, XX-Large
Optimus Prime Costume
  • Orville
Rubie's mens Star Trek the Next Generation Deluxe Commander Picard Adult Shirt Costume Top, Red, Extra-Large US
Orville Costume
  • Oliver Twist
Smiffys Victorian Poor Peasant Boy Kit
Oliver Twist Costume
  • Olympia
Underwraps Women's Sexy Gladiator Costume-Olympia, White, Small
Olympia Costume
  • Oompa Loompa
Rubie's mens Willy Wonka and the Chocolate Factory Deluxe Oompa Loompa Adult Sized Costume, As Shown, Standard US
Oompa Loompa Costume
  • Olivia
  • Otis
  • Obelix
  • Odie
  • Osmosis Jones

Find all the characters beginning with O costumes right here.

Celebrities Beginning with O Costumes

  • Oprah Winfrey
  • Olivia Newton John
  • Owen Wilson
  • Olivia Rodrigo
  • Orlando Bloom
  • Otis Redding
  • Olivia Wilde
  • Oliver Stone
  • Oliver Hardy
Oliver Hardy Adult Costume, X-Large
Oliver Hardy Costume
  • Ozzy Osbourne
Forum Novelties mens 80's Super Rocker Ozzy Costume Wig Party Supplies, Black, One Size US
Ozzy Osbourne Costume

Historical Costumes that Start with O

  • Oscar Wilde
  • Orville Wright
  • Oskar Schindler
  • Osman I
  • Barack Obama
Deluxe Barack Obama
Barack Obama Costume

Find all the famous people (celebrities and historical) fancy dress starting with O costumes right here.

Food Beginning with O Costumes

  • Onion
Adult Onion Costume - ST
Onion Costume
  • Orange
Rasta Imposta Orange Slice Halloween Costume, Ladies, One Size Fits Most
Orange Costume
  • Oregano
OREGANO Easy Halloween Costume T-Shirt
Oregano Costume
  • Oreo
Rasta Imposta Oreo Cookie Costume Adult One Size
Oreo Costume
  • Olives
Rasta Imposta Olive Jar Colossal Condiment Halloween Costume, Adult One Size
Olive Jar Costume
  • Olive Oil
  • Oysters
  • Omelette
  • Okra
  • Onion Rings
  • Oxtail
  • Oat Milk
  • Oyster sauce

Find all the food starting with O costumes right here.

Animals Beginning with O Costumes

  • Octopus
Blue Octopus Costume for Adults X-Large
Octopus Costume
  • Owl
LZBXBXDA Unisex Adult Snowy owl Onesie One Piece Pajamas Animal Christmas Costume Homewear Sleepwear for Women men
Owl Costume
  • Otter
Adult Otter Costume - M
Otter Costume
  • Ostrich
Adult Ostrich Costume, Unisex Plush Ostrich Jumpsuit, African Safari Bird Outfit Small
Ostrich Costume
  • Orangutan
Orange Orangutan Adult Costume Small
Orangutan Costume
  • Ocean creature
Spooktacular Creations Inflatable Costume Full Body Squid Air Blow-up Deluxe Halloween Costume - Adult Size
Ocean Creature Costume

Find all the animals starting with O costumes right here.

Pet Costumes that Start with O

  • Oscar the Grouch
Pet Krewe Large Oscar The Grouch Dog Costume & Cat Costume Medium - Perfect for Halloween, Christmas Holiday, Parties, Photoshoots, Gifts for Dog & Cat Lovers
Oscar the Grouch Pet Costume
  • Octopus
Dog Cat Octopus Costumes,Pet Halloween Cosplay Costume for Small Puppy Dogs
Octopus Pet Costume
  • Oompa Loompa
Rubie's Willy Wonka Oompa Loompa Pet Costume and Wig, As Shown, Medium
Oompa Loompa Pet Costume
  • Owl
Dog Costume Realistic Funny Owl Cosplay Hat Halloween Costume Cat Apparel for Cats Small Dogs Ideal for Halloween, Dog Birthday, Dog Cosplay, Dog Outfits, Pet Clothes
Owl Pet Costume
  • Ox
Halloween Dog Horn Wig Soft Bull Dog Costumes Winter Warm Hat Dog Wig Clothes Pet Funny Ox Hat Dog Cat Horn Headgear Accessories Cosplay Bull Mane for Medium to Large Dogs Outfit (Large)
Ox Pet Costume
  • Oktoberfest
Pet Krewe German Oktoberfest Dog Costume & Cat Costume Medium - Barktoberfest Halloween Dog Costume - Perfect for Halloween, Christmas Holiday, Parties, Photoshoots, Gifts for Dog & Cat Lovers
Oktoberfest Pet Costume
  • Olaf
Rubie's unisex adult Disney: Frozen 2 Olaf Pet Costume Party Goods, White, M Neck 14.5 Girth 20 Back 15 US
Olaf Pet Costume
  • Optimus Prime
Rubie's Transformers Optimus Prime Deluxe Pet Costume, X-Large
Optimus Prime Costume

Find all the pet costumes starting with O right here.

Couples Costume Ideas Starting with O

  • Oreos
Rasta Imposta Couples Costume - Milk-n-Cookies Dunk Your Oreo in Glass of Milk, Adult One Size, Black and White
Oreo and Milk Couple Costume
  • Olive Oyl and Popeye 
Future Memories Popeye and Olive Oyl Costume Set (Popeye STD/Olive M/L)
Olive Oyl and Popeye Costume


Find all the couples costumes starting with O right here.

Jobs that Start with O Costume Ideas

  • Office Manager
  • Office Clerk
  • Obstetrician
  • Optometrist
  • Orthodontist
  • Orthopedic Surgeon
  • Occupational Health and Safety officer

Countries Starting with O Costumes

  • Oman
Oman T-Shirt
Oman T Shirt

Why not wear a tshirt with the Oman flag on it – or their traditional dress.

Colors for Costumes Beginning with O

  • Orange
  • Olive
  • Orchid
  • Ochre
  • Oak Brown
  • Oak
  • Ocean Blue
  • Ocean Green
Original Morphsuit Fancy Dress Costume ,Orange, Large
Orange Morphsuit

Why not wear a costume in one of the O colors above? Or wear a orange or olive morphsuit if you dare!

Sports Starting with O Costume Ideas

  • Off-Road Racing
  • Oztag
  • Outrigger Canoeing
  • Orienteering
  • Obstacle Course Racing
  • Ocean Rowing

Baby Costumes Starting with O

Firstly you must check out this gorgeous Mom and baby costume: An Octopus and Diver costume!

Seeing Red Expert Diver & Squirmy Octopus Size O/S Includes Mask, Flipper Shoe Covers, Octopus Carrier Cover & Matching Headpiece
Octopus and Diver Mom and Baby Costume

Here are some other fun baby costumes you don’t want to miss.

  • Oscar the Grouch
Sesame Street Oscar Baby Carrier Costume Standard
Oscar the Grouch Baby Carrier Costume
  • Octopus
LY WONDERFUL Halloween 3-24M Animal Peacock Lobster Octopus Cat Baby Toddler Funny Costume Cosplay Romper (Octopus, 12-18 Months)
Octopus Baby Costume
  • Olaf
Disguise Baby's Disney Frozen Olaf Deluxe Toddler Costume,White,Toddler XS (12-18 mths)
Olaf Baby Costume
  • Owl
UNDERWRAPS unisex baby Baby's Owl infant and toddler costumes, Brown, 18M-24M US
Owl Baby Costume
  • Optimus Prime
Optimus Prime Rescue Bot Toddler Muscle Costume, Red/Blue, Toddler Large
Optimus Prime Baby Costume
  • Olivia
Rubie's Deluxe Olivia Costume Pig Toddler
Olivia Baby Costume
  • Oompa Loompa
Toddler Willy Wonka Oompa Loompa Costume - 2T
Oompa Loompa Baby Costume
  • Ox
Rubie's Baby Ugly Dolls Ox Infant Costume, As Shown
Ox Baby Costume
  • Otis the Owl
Princess Paradise Otis The Owl Toddler Costume
Otis the Owl Baby Costume

Find all the baby costumes that start with O right here.

If you need a costume party theme don’t miss our fun guide to the best dress up party themes for adults.

Costumes Beginning with O

If you’ve looked through the full list right here – but are still looking for a more a low-key costume then check out these t-shirts below. They totally count as an easy O costume.

Sesame Street Oscar The Grouch Face T Shirt & Stickers (XX-Large)
Oscar the Grouch Shirt
I'm Not A Short Person...I'm Just A Tall Oompa Loompa shirt.
Oompa Loompa Shirt

I sincerely hope you love these fun fancy dress beginning with O ideas and you found the perfect fancy dress costume idea for your next dress up party.

Don’s miss our other fun costume ideas:

Costumes starting with A

Costumes starting with B

Costumes starting with C

Costumes starting with D

Costumes starting with E

Costumes starting with F

Costumes starting with G

Costumes starting with H

Costumes starting with I

Costumes starting with J

Costumes starting with K

Costumes starting with L

Costumes starting with M

Costumes starting with N

Costumes starting with P

Costumes starting with R

Costumes starting with S

Costumes starting with T

Costumes starting with W

Costumes starting with Y

Big Guy Halloween Costume Ideas

Please pin for later or so that you can find us for next Halloween or dress up party.

costumes that start with o


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