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Costume Ideas Starting With the Letter O

Hi, I am Adele. I've been running a large fancy dress shop in Essex, England, since 1998. I'm happy to pass on my knowledge to help others.

Hosting or attending a themed party where guests need to dress up as a person or thing that starts with the letter O? Here are some ideas to inspire you!

Hosting or attending a themed party where guests need to dress up as a person or thing that starts with the letter O? Here are some ideas to inspire you!

Planning a Party With a Letter O Theme?

Giving your guests a letter as a costume theme is quite common and can make for some very interesting costume ideas. You have a few options:

  • Allow guests to dress up in a costume related to their initials (or instruct them to choose a costume beginning with the first letter of their first name if you want to simplify their options).
  • Ask guests to dress up in costume ideas beginning with the same letter as your name.
  • Choose one or two letters that they have to find a related costume for.

When you first send out your invitations, some of your guests may be confused about what you are asking for. I suggest that in the invitation you give a thorough explanation and provide a few costume suggestions. If your guests are confused, they may not even attempt to dress up, or worse, they may not attend your party.

So, this article will focus on costume ideas beginning with the letter O. If you have any other great costume ideas, pop them in the comments section at the end of the article, and I will add them in.

The Oompa Loompa costume is a classic look that transcends generations.

The Oompa Loompa costume is a classic look that transcends generations.

  • O Ren Ishii (aka Cottonmouth): A member of the Deadly Vipers Assassination Squad and a Tokyo gang leader in the Tarantino film Kill Bill. She is half Chinese, half American-Japanese. Costume involves a full kimono with obi—essentially geisha-style without the heavy make-up. She is armed with a ninja-style sword.
  • Obama, Barack: 44th president of the United States of America. Several versions of overhead and cardboard masks of the president are available on the market.
  • Oberon: King of the fairies from William Shakespeare’s A Midsummer Night’s Dream. The opportunity for creativity is boundless. As a fantasy figure, Oberon is traditionally portrayed either as a woodland earth spirit, using shades of green and brown for clothing, skin, and hair, or a traditional fairy, using greens, blues, lilacs, or silvery glitter fabrics, wings, etc. A spectacular effect can be created using silver and gold glitter fabrics and UV-reactive and metallic makeup products for a more supernatural/science fiction approach.
  • Obi-Wan Kenobi: Leading Jedi Knight character in the original Star Wars film (later renamed Episode Four: A New Hope). Played by Sir Alec Guinness, Obi-Wan acts as a mentor to Luke Skywalker prior to his meeting with his nemesis, Darth Vader. Obi-Wan wears the standard Jedi outfit of brown robes over a white tunic and trouser outfit and, of course, carries a lightsaber.
  • Octopus: Octopi are traditionally grey/blue/black in color, although a toy version, Stretch, seen in Toy Story 3, is purple! Although outfits can be found, depending upon how they are designed, the tentacles can prove a practical problem for parties!
  • Octopussy Operative: From the James Bond film Octopussy. Octopussy is a female circus owner, but the circus acts as a cover for other more devious activities. The "operatives'" "day jobs" are as acrobats within the circus. The costume comprises a red catsuit with a small octopus symbol on the left breast, Eastern yashmak-style headdress. Weaponry may wary.
  • Oddjob: Bond villain from James Bond film Goldfinger. He is Korean, mute, and stocky. The costume comprises a black two-piece suit and bowler hat.
  • Oengus: Irish god of love, also known as Mabon and Maponus. Against the dark costume trend found with many Celtic gods, this god is associated with aspects of light blue, gold, and white. The white recognizes his love of the swan-maiden Caer, whom he pursued disguised as a swan one Samhain/Celtic New Year.
  • Ogre: Traditionally a large, cruel, and ugly humanoid monster of folklore and legend. Several ogre-style overhead masks can be found for Halloween, etc. In the pantomime Puss-in-Boots, an ogre is the main villain of the piece. However, the best-known ogre of recent years is Shrek, hero of four films (and several seasonal "shorts"). Aside from working for a movie- or animation-themed event, Shrek is also a genuine book character when it comes to World Book Day.
  • Officer and a Gentleman: This US Naval officer look is a popular one for 1980s parties and one that many men are prepared to wear. It is based on the 1982 film of the same name, starring Richard Gere as Officer "Zack" Mayo. The costume will also work for a professions/what-I-want-to-be-when-I-grow-up party. It usually consists of a white naval suit with black and gold trim and a matching peaked cap.
  • Oil Spill Technician (BP): The costume industry jumped on a contemporary bandwagon a few years ago and, as a result of the BP oil rig fire and the subsequent disastrous oil leak into the Gulf of Mexico, produced an outfit based on BP oil-stained overalls.
  • Oktoberfest Celebrant: Oktoberfest is a German festival (with versions also found in European countries such as Belgium), which, despite the name, actually starts in late September. Much drink (usually beer) is consumed, and in Germany, Munich is the main center of celebrations. Traditional German wear such as Lederhosen, shirts, and caps for men and dirndl skirts worn with lace petticoats and an apron for women may be worn, although fancy-dress costumes and unusual headgear are also seen.
Channel the force with an Obi Wan Kenobi costume.

Channel the force with an Obi Wan Kenobi costume.

  • Old Mother Hubbard: English nursery rhyme character who allegedly suffered a dog-food shortage crisis. Given that granny-style costumes are available, along with a dog outfit, this might make the basis of a couple's costume.
  • Old-Time Music Hall: OTMH was a form of entertainment popular in the British late-Victorian and Edwardian periods involving a variety of acts performing in specialist theatre-like venues, often adjacent to pubs and drinking houses. An opportunity to get out your late Victorian or Edwardian-style costumes.
  • Olive Oyl: Cartoon character who was the stick-thin girlfriend of Popeye the Sailor Man, popular on TV in the 1960s. Also noted for her pigtails, an official costume has recently become available.
  • Oliver Cromwell: A major character in the Stuart period of British history. Following the Civil War in which the Royalist followers of King Charles I were defeated by the Parliamentarians and the king was executed, there followed a period of puritan "Commonwealth." During this time, Christmas was canceled, and Cromwell, as Lord Protector of England, was the nearest thing the country had to a ruler. When Cromwell died, he was succeeded by his son, but the nation’s mood changed, leading to the Restoration of Charles II. A costume is in black or brown somber colors—a roundhead helmet, if available, is a bonus.
  • Oliver Hardy: With partner Stan Laurel, Laurel & Hardy were the classic "little and large" comedy duo of early cinema. Costume(s) usually consist of suits and bowler hats, although they are seen in other guises such as removal men, legionnaires, etc.
  • Oliver Twist: The leading character from the book of the same name by Charles Dickens. Abandoned as a baby at a Victorian workhouse in London, Oliver suffers several reversals of fortune, including falling in with Fagin and his gang of young thieves and pickpockets. Shirt, ragged trousers, cap, wooden bowl.
  • Onion Seller: Probably the male equivalent to the French maid as a stereotypical French costume, using the classic Breton-style stripe jumper and black beret. Plastic onions are probably best substituted for the real thing!
  • Oompa Loompa: The Oompa-Loompas are workers employed by Willie Wonka in Roald Dahl’s Charlie and the Chocolate Factory. Although it is generally agreed that they are of small stature, their appearance has changed from being African pygmies in early versions of the book to white with golden hair in later versions. Also, on film in the 1971 movie, they were orange-skinned with greenish hair, while in the later 2005 film (featuring Johnny Depp), they were normal looking but in red tracksuits (although through technically wizardry, the same actor actually played all the Oompa-Loomas).
  • Opera Singer: A "Wobbly" Pavarotti costume is always a good option, and for the female, the Wagnerian Brunhilde warrior or "Madam Butterfly," from Puccini's opera of the same name, may be used
  • Operation: Licensed costume based on the popular children’s game of the same name.
  • Ophelia: Tragic daughter of Polonius in Shakespeare’s Hamlet. She is in love with Hamlet, the Danish Prince, but he is somewhat obsessed with the recent death of his father, with ghosts suggesting the father was murdered. Spoiler alert: Her love is unrequited, and she eventually takes her own life.
  • Optimus Prime: A fictional character from the Transformers TV cartoon series and recent movies. He is the leader of the Autobots and, in his battle against the evil Decepticons, he can transform himself into an American-style articulated lorry. A children’s costume is available in some areas.
  • Orange: In theory, it's a simple costume, but finding material of the right dimpled texture may be a problem. An alternative is the sumo-style Tango-man, used to promote the orange drink a few years ago.
  • Orang-utan: The word translates as "Man of the Forest," and the Orang-utan is one of the most intelligent of primates. An Orang-utan costume might be thought to have limited appeal over, say, a gorilla outfit but for the fact that an orang-utan is a Librarian at the Unseen University in the Discworld novels of Terry Pratchett.
  • Orc: Tough and warlike humanoid creatures found in fantasy literature and media. Possibly best known nowadays through their portrayal in the Lord of the Rings books of J.R.R. Tolkien and the subsequent films of those stories. To this end, several official Orc costumes and masks exist, in addition to those that might be found from cosplay and live-action roleplay suppliers and costume hire outlets.
  • Oreo: A much-loved American biscuit/cookie of which some costumes do exist!
Unfortunately, beers aren't included with this Oktoberfest Celebrant costume.

Unfortunately, beers aren't included with this Oktoberfest Celebrant costume.

  • Organ Donor: A variation on those slightly gruesome "bleeding patient"-style or zombie costumes that have "exposed innards" (often with blood effects). As a more subtle approach, just wear a badge that says "Organ Donor - See inside for details."
  • Orion Slave Girl: Given that this is a green-skinned girl in a skimpy bikini-style outfit first seen in the original Star Trek series (but recurring since), it's quite a popular choice at conventions and sci-fi parties!
  • Orphan Annie: Originating from the Little Orphan Annie comic strip, the character now has a new lease of life thanks to the Annie stage musical and film. Typical Annie look is a short curly ginger wig and spotted dress, sometimes with under-petticoats.
  • Orpheus: In Greek myth, Orpheus was such an accomplished poet and musician that he charmed Pluto, God of the Dead and ruler of Hades, to allow his wife, Eurydice, back from the Underworld when she was killed by a snake-bite. Unfortunately, he looked back at the last minute before reaching the safety of the Upperworld, and Eurydice was reclaimed by Pluto.
  • Osama Bin Laden: An Osama mask exists, and some don’t even bother with the Eastern robes, using garbage bags for "Osama Bin Liner."
  • Oscar Statue: The Oscar statue (or "American Academy Award Statuette") is an iconic symbol of the movies. Although an appropriate costume has existed for several years, the recent advent of all-in-one Morph suits in all colors, including gold, offers a potential alternative option.
  • Oscar the Grouch: Character from the children's TV show Sesame Street. This furry, slightly bad-tempered personality lives in a garbage bin, and this is reflected in the official costume in which the bin comes as part of the outfit.
  • Oscar Wilde: Writer and poet of the Victorian era, known for his flamboyant style of dress and his cutting wit: "There is only one thing worse than being talked about, and that is not being talked about."
  • Osmonds: An all-male group of brothers from the early 1970s. Famous for their dazzling white teeth, white matching stage-suits, and immaculate hairstyles, these days, the best known of the Osmonds are Donny, Marie, and "Little" Jimmy.
  • Ostrich: Not so much an ostrich as such (neck’s a little tricky for a costume!), but the ever-popular ride-on variety popularized by Bernie Clifton in the 1980s.
  • Outlaw: The British tend to associate the term "outlaw" with Robin Hood, the well-known folk hero. Elsewhere, outlaws usually tend to be associated with the Wild West, with names such as Billy the Kid, although a pirate or major villain/villainess can be alternative choices.
  • Outlet & Plug: The "electrical outlet/socket and plug" couple costumes are one of a series of "paired" outfits available on the market. Typically, they are built from printed foam and hence are easy to wear, if a little unusual.
  • Owl: Because of its compact body shape, the owl lends itself to a costume better than most birds. Aside from some superb large head mascot-style costumes, a number of more conventional outfits (including one for Hedwig, Harry Potter’s owl) are available on the market.
  • Ozymandias: One of the characters in the graphic novel and subsequent film Watchmen. Ozymandias (originally an alternate name for the Pharaoh Ramesses II of Egypt in a poem by Percy B. Shelley) is the alter-ego of Adrian Veidt, supposedly "the smartest man on the planet" and one-time costumed vigilante. In the wake of the film, an outfit based on his owl-like costume has become available.
  • Ozzy Osbourne: Musician who originally rose to fame as a leading member of the heavy metal band Black Sabbath but nowadays shares the celebrity spotlight with his wife/manager Sharon and two of their children Kelly and Jack. The classic Ozzy look is long black hair, round-rim glasses, and black wear of any kind—Black Sabbath t-shirts, cloaks, etc., may enhance the look.

Have you got any great O-themed costume ideas?

Super Cool Pinned - Halloween Tips on November 03, 2013:

Octopus for women would be much better.

quemacoco on January 17, 2011:

very interesting. never thought about doing a party with a start letter.

NikitaButalia on January 17, 2011:

This is great! Sounds like so much fun. I love fancy dress parties, but never thought of such an idea!