| O'ryan | 37 | Singer | Omarion's Younger Brother |
| O'Shea Russell | | Model | Ex-Boyfriend of Erica Dixon |
| O'Sht | | Other | Black Ink, reality show |
| O-Lan Jones | | Actress | Ex spouse of Sam Shepard |
| O. J. Mayo | 36 | Basketball | NBA Shooting Guard |
|
| O.J. Simpson | 76 | Football | Former Running Back for the Buffalo Bills |
| O.T. Genasis | 36 | Rapper | CoCo, single |
| Obadele Thompson | 47 | Track and Field | First Barbadian to win Olympic Bronze medal in 100m |
| Obie Bermudez | 47 | Musician | is a Latin pop singer and composer |
| Octavia Spencer | 51 | Actress | The Help, film |
| October Gonzalez | | Spouse | Wife of Tony Gonzalez |
| Oded Fehr | 53 | Actor | Ardeth Bay in the Mummy |
| Odell Beckham, Jr. | 31 | Football | NFL Wide Receiver |
| Odessa Whitmire | 49 | Other | Ex girlfriend of Matt Damon |
| Odette Annable | 38 | Actress | Role in "South Beach" and "October Road" |
| Odile Rodin | | Spouse | Spouse of Portfirio Rubirosa |
| Offset | | Rapper | Migos, rap trio |
| Ojani Noa | 49 | Restauranteur | Ex spouse of Jennifer Lopez |
| Oksana Baiul | 46 | Skater | 1994 Olympic Champion |
| Oksana Emelianenko | | Spouse | Spouse of Fedor Emelianenko |
| Oksana Grigorieva | 54 | Musician | Girlfriend of Mel Gibson |
| Oksana Pochepa | 39 | Musician | Affair with Mel Gibson |
| Ol' Dirty Bastard | 35* | Rapper | Wu-Tang Clan, rap group |
| Ola Brunkert | 61* | Musician | Drummer for the group "ABBA" |
| Ola Jordan | 41 | Other | British TV Show "Strictly Come Dancing" |
| Ola Ray | 63 | Other | Co-Star of Thriller, video |
| Olaf Bjoern | | Agent | Ex-Boyfriend of Nadja Auermann |
| Olaf Thommesen | | Other | Spouse of Vendela Thommessen |
| Olalla Dominguez | | Other | |
| Olatz Lopez Schnabel | | Spouse | Wife of Julian Schnabel |
| Olden Polynice | 59 | Basketball | Detroit Pistons |
| Oldrich Kaiser | 68 | Actor | Spouse of Nada Konvalinkova |
| Ole Koretsky | | Musician | Boyfriend of Dolores O'Riordan |
| Ole Schroder | 52 | Other | |
| Oleg Cassini | 92* | Designer | noted for being chosen by Jacqueline Kennedy to design her state wardrobe in the 1960s. |
| Olesya Rulin | 38 | Actress | Kelsi Nielsen of High School Musical |
| Oletha 'Lee' Ludwig | | Spouse | Wife of Gary Hart |
| Olga Gazhiyenko | 37 | TV Personality | |
| Olga Khokhlova | 63* | Other | Ballerina of the Ballet Russes |
| Olga Korotyayeva | 43 | Actress | Relationship with Sean Penn |
| Olga Kurylenko | 44 | Actress | Bond girl Camille in Quantum of Solace, film |
| Olga Lazovich Milanov | | Spouse | Widow of Frank Lloyd Wright |
| Olga Rudge | 101* | Musician | Violinist |
| Olga San Juan | 81* | Actress | |
| Olga Sosnovska | 51 | Actress | Lena Kundera "All My Children" |
| Olga Tanon | 56 | Singer | Latin Pop Artist |
| Olga Yurevna Lysova | | Spouse | First spouse of Roman Abramovich |
| Oli Green | | Actor | Relationship with Sienna Miller |
| Oli Higginson | 29 | Actor | Jamie Wellerstein in Full Cast Crew, film |
| Olive de Wilton | | Actress | |
| Olive Eleanor Custance | 70* | Artist | Poet |
| Olive Ireland | | Spouse | |
| Olive Osmond | 79* | Spouse | Mother of The Osmonds |
| Olive Stokes | 85* | Actress | |
| Olive Thurman | | Director | stage director |
| Oliver Bender | 41 | Actor | Tim Bocking in GZSZ |
| Oliver Cheshire | 35 | Model | Relationship with Pixie Lott |
| Oliver Dimsdale | 51 | Actor | |
| Oliver Hardy | 65* | Actor | Laurel & Hardy movies |
| Oliver Hudson | 47 | Actor | Rules of Engagement |
| Oliver Kahn | 54 | Soccer | Retired German Goalkeeper |
| Oliver Mellor | 43 | Actor | Dr. Matt Carter in "Coronation Street" |
| Oliver North | 80 | Other | Iran-Contra scandal |
| Oliver Parker | 55 | Producer | An Ideal Husband |
| Oliver Peck | | Artist | Spouse of Kat Von D |
| Oliver Phelps | 38 | Actor | George Weasley in "Harry Potter" |
| Oliver Platt | 64 | Actor | |
| Oliver Pocher | 46 | Comedian | is a German actor, stand-up comedian and television host |
| Oliver Stark | 32 | Actor | Evan 'Buck' Buckley in 9-1-1, Fox series |
| Oliver Stone | 77 | Producer | a director with a series of films about the Vietnam War |
| Oliver Sykes | 37 | Singer | Bring Me The Horizon, band |
| Oliver Tobias | 76 | Actor | King Arthur in the TV series Arthur of the Britons |
| Oliver Trevena | 42 | Actor | Terry in The Long Road, film |
| Oliver Vanetta Lynn | 69* | Spouse | Relationship with Loretta Lynn |
| Oliver Withcomb | | Other | a martial-arts instructor |
| Oliver Wnuk | 48 | Actor | Boyfriend of Yvonne Catterfeld |
| Oliver Wood | 80* | Other | Cinematographer for The Bourne Identity, film |
| Olivia | 43 | Singer | Bizounce, single |
| Olivia Bolton | | Internet Personality | Relationship with Tom Holland |
| Olivia Bonamy | | Actress | |
| Olivia Brown | 63 | Actress | Det. Trudy Joplin "Miami Vice' |
| Olivia Burwell | | Spouse | |
| Olivia Colman | 50 | Actress | Anne, Queen of Great Britain in The Favourite |
| Olivia Culpo | 31 | Model | Miss Universe 2012 |
| Olivia d'Abo | 55 | Actress | perhaps best known for her role as "Karen Arnold" on The Wonder Years |
| Olivia de Havilland | 104* | Actress | Melanie Wilkes in Gone with the Wind |
| Olivia English | | Spouse | Ex-wife of Todd English |
| Olivia Flowers | 31 | Actress | Relationship with Austen Kroll |
| Olivia Hallinan | 39 | Actress | Laura Timmins In "Lark Rise to Candleford" |
| Olivia Holt | 26 | Actress | Kim in Kickin' It, Disney XD series |
| Olivia Holzmacher | | Other | Relationship with Joe Burrow |
| Olivia Hussey | 72 | Actress | Juliet in Franco Zeffirelli's 1968 film version of Romeo and Juliet |
| Olivia Jade | 24 | Blogger | Social Media, Daughter of Lori Loughlin |
| Olivia Jean | 34 | Musician | Lead singer in band, The Black Belles |
| Olivia Manning | | Spouse | Wife of Pro Football Player Archie Manning |
| Olivia Millar | | Entrepreneur | Relationship with Johan Hill |
| Olivia Modling | | Other | Relationship with Will Forte |
| Olivia Munn | 43 | Actress | Co-Host of Attack of the Show! |
| Olivia Newton-John | 73* | Singer | Grease, musical |
| Olivia O'Flanagan | | Spouse | |
| Olivia Palermo | 38 | Actress | The City, MTV series |
| Olivia Pickren | 30 | Model | Dating Steven McQueen |
| Olivia Poulet | 46 | Actress | |
| Olivia Rodrigo | 21 | Actor | Nini Salazar-Roberts in the High School Musical series |
| Olivia Thirlby | 37 | Actress | Leah in "Juno" |
| Olivia Trinidad Arias | 75 | Spouse | Widow of George Harrison of The Beatles |
| Olivia Wilde | 40 | Actress | Remy "Thirteen" Hadley in House, Booksmart |
| Olivia Williams | 55 | Actress | Jane Fairfax in the British TV film Emma |
| Olivier Chandon de Brailles | | Heir | heir to the Moet-Chandon Champagne fortune |
| Olivier Giner | | Other | Fiancee of Amy Jo Johnson |
| Olivier Maier | | Executive | Duke of Provence, Relationship with Danielle Staub |
| Olivier Martinez | 58 | Actor | Alex "Le Loup Rouge" Montel in S.W.A.T., film |
| Olivier Maury | | Other | Ex-Husband of Anggun |
| Olivier Rousteing | 38 | Designer | Creative Director of Balmain |
| Olivier Sarkozy | 54 | Banker | Half-brother of Nicolas Sarkozy |
| Olly Murs | 39 | Musician | Runner-Up in "The X Factor" in 2009 |
| Olof Inger | | Other | Ex fiance of Robyn |
| Olu Evans | | Lawyer | Relationship with Misty Copeland |
| Oluchi Onweagba | 43 | Model | Nigerian Supermodel. |
| Olympia Dukakis | 89* | Actress | Moonstruck, film |
| Olympia Scott | 47 | Basketball | "WNBA" |
| Omar Benson Miller | 45 | Actor | Walter Simmons in CSI: Miami, tv series |
| Omar Bravo | 44 | Football | plays for Deportivo de La Coruna in Spanish La Liga. |
| Omar Epps | 50 | Actor | Quincy McCall in Love and Basketball, film |
| Omar Gooding | 47 | Actor | Brother of Cuba Gooding, Jr. |
| Omar Khyami | | Other | Ex-boyfriend of Tamara Ecclestone |
| Omar Rodriguez-Lopez | 48 | Other | |
| Omar Sharif | 83* | Actor | "Lawrence of Arabia" and "Dr. Zhivago" |
| Omargy Ibrahimo | | Royalty | Spouse of Marisol Nichols |
| Omari Hardwick | 50 | Actor | James "Ghost" St. Patrick in Power, Starz series |
| Omarion | 39 | Singer | Lead singer for B2K, r&b group |
| Omarosa Manigault | 50 | TV Personality | Contestant on The Apprentice, NBC series |
| Omer Bhatti | 40 | Rapper | Alleged Son of Michae Jackson |
| Omer Fedi | 24 | Producer | Songwriter and Producer from top musical acts |
| Omid Djalili | 58 | Agent | British Iranian stand-up comedian |
| Omri Katz | 47 | Actor | played the role of John Ross Ewing III, the son of J.R. Ewing |
| On-on Yu | | Scientist | Ex spouse of Chow Yun Fat |
| Oni Souratha | | Director | Fiancee of Mekhi Phifer |
| Ooi Hoe Seong | | Executive | Relationship with Li Gong |
| Oona O'Neill | 65* | Spouse | Charlie Chaplin's fourth wife |
| Oona Todd-Naylor | | Other | |
| Opal Anchel | | Actress | Arianna Shapour Thornhart on the popular soap opera, Port Charles |
| Opal Stone | | Designer | Spouse of Ron Perlman |
| Ophelie Winter | 50 | Singer | French singer and actress |
| Oprah Winfrey | 70 | Talkshow Host | The Oprah Winfrey Show |
| Oral Roberts | 91* | Heir | Founder of Oral Roberts University |
| Oren Haglund | | Other | |
| Orfeh | 57 | Actress | |
| Orianne Cevey | | Spouse | Relationship with Phil Collins |
| Oriel | | Other | Ex-Girlfriend of Offset |
| Oriela Medellin Amieiro | 38 | Other | Girlfriend of Russell Brand |
| Orish Grinstead | | Singer | 702, r&b singing group |
| Oriste Williams | 37 | Singer | JLS, band |
| Orjan Ramberg | 76 | Actor | Swedish Actor |
| Orlando Bloom | 47 | Actor | Legolas in The Lord of the Rings, films |
| Orlando Brown | 36 | Actor | Eddie Thomas of That's So Raven, television show |
| Orlando Brown | 40* | Restauranteur | Former Defensive Tackle for the Cleveland Browns |
| Orlando Cabrera | 49 | Baseball | is a Major League Baseball shortstop |
| Orlando Gordon | | Other | Fiance of Deelishis |
| Orlando Jones | 55 | Actor | MADtv, television sketch comedy |
| Orlando Scandrick | | Football | Dallas Cowboys |
| Orlando Wells | 50 | Actor | Alex Stanton in the Channel 4 teen drama, As If |
| Orly Marley | | Spouse | Wife of Ziggy Marley |
| Ornella Muti | 69 | Actress | Princess Aura "Flash Gordon" |
| Orsi Feher | | Model | |
| Orson Bean | 91* | Actor | Loren Bray on Dr. Quinn Medicine Woman |
| Orson Salazar | | Executive | Relationship with Paz Vega |
| Orson Welles | 70* | Actor | H. G. Wells "The War of the Worlds" |
| Osama bin Laden | 54* | Other | Founder of al-Qaeda and Attacks Against the United States of America |
| Oscar De La Hoya | 51 | Boxer | Ten-Time World Title Champion in Ten Different Weight Divisions |
| Oscar de la Renta | 82* | Designer | |
| Oscar G. Mayer | | Executive | Chairman of meat-processing company that bears his name |
| Oscar Hammerstein II | 65* | Other | was an American writer, producer and director of musicals for almost 40 years |
| Oscar Isaac | 45 | Actor | Politician Nick Wasicsko in Show Me a Hero series |
| Oscar Lerman | 72* | Other | art gallery owner |
| Oscar McBlack | | Musician | Hell City Glamours |
| Oscar Nunez | 65 | Actor | Oscar Martinez on The Office |
| Oscar Pistorius | 37 | Track and Field | The First Double Leg Amputee to Participate in The Olympic Games |
| Oscar Robinson | | Spouse | Husband of Esther Rolle |
| Oscar Wilde | 46* | Playwright | Author of 'Dorian Gray', 'Importance of Being Earnest' |
| Osgood Perkins | 45* | Actor | Father of Anthony Perkins |
| Osi Umenyiora | 42 | Football | NFL Defensive End |
| Oskar Werner | 61* | Actor | |
| Osmariel Villalobos | 35 | TV Personality | Miss Earth Venezuela in 2011 |
| Ossama Fathi Rabah Al-Sharif | | Other | Spouse of Xenia Deli |
| Ossie Davis | 87* | Actor | Do The Right Thing, film |
| Osvaldo Sabatini | | Spouse | Spouse of Catherine Fulop |
| Oswald Gooden | | Spouse | |
| Oswaldo Castillo | | Actor | The Adam Carolla Show |
| Otis Nixon | | Other | |
| Otis Redding | 26* | Singer | |
| Otis Williams | 82 | Singer | Member of the Temptations, group |
| Ottavia Busia | | Spouse | Spouse of Anthony Bourdain |
| Ottilie Assing | 165* | Other | Affair with Frederick Douglass |
| Otto Frank | 91* | Spouse | father of Anne Frank |
| Otto Preminger | 79* | Director | for stylish film noir mysteries such as Laura (1944) |
| Ousmane Sembene | 84* | Director | |
| Ove Dahlberg | | Spouse | |
| Owain Walbyoff | 42 | Producer | Fiance of Natalie Pinkham |
| Owain Yeoman | 45 | Actor | Wayne Rigsby in "The Mentalist" |
| Owen Baylis | | Spouse | Ex spouse of Rae Dawn Chong |
| Owen Benjamin | 43 | Actor | The House Bunny |
| Owen Hart | 34* | Wrestler / WWF | WWF |
| Owen Joyner | 23 | Actor | Alex in the Netflix series, Julie and the Phantoms |
| Owen LaFave | | Other | Ex-Husband of Deborah LaFave |
| Owen Moore | 52* | Actor | Ex spouse of Mary Pickford |
| Owen Wilson | 55 | Actor | Anthony Adams in Bottle Rocket, film |
| Oyo Boy Sotto | 40 | Actor | the son of the famous television host, actor and comedian Vic Sotto |
| Oz Perkins | 50 | Actor | Son of Anthony Perkins |
| Ozuna | 32 | Singer | |
| Ozzie | | Other | |
| Ozzie Nelson | 69* | Actor | The Adventures of Ozzie and Harriet radio and television series |
| Ozzy Osbourne | 75 | Singer | Black Sabbath |