Series A to Z
- O Canada National Film Board of Canada 1
- O-Genki Clinic ACC Productions 1
- O'B & D Film Productions 1
- O'Grady Soup2Nuts 19
- Oakie Doke Cosgrove Hall Films 1
- Oase Filmproduktion 3
- Oasis Europkikara 1
- OB Planning 2
- Obake no Hori Apollon Create 1
- Obake no Q-tarô TMS Entertainment 1
- Ōban Star-Racers Jetix Concept Animation 26
- Obez'yanki Soyuzmultfilm 5
- The Oblongs Film Roman Productions 13
- Obtain 3
- Ochame Na Futago: Claire Gakuin Monogatari TMS Entertainment 26
- Ochamegami Monogatari Kokoro Polon Kokusai Eigasha 1
- Octonauts Brown Bag Films 76
- Odd Job Jack Smiley Guys Studios 39
- The Oddball Couple DePatie-Freleng Enterprises 32
- OddBot 1
- Oddsock Cartoons 1
- Odessa Fabrika VUFKU 2
- Odessa Animation Studio 1
- Odoltogi 2
- ODSK 1
- Odyssey Pictures Corporation 1
- Ofensiva Contra El Enemigo Instituto Cubano del Arte e Industrias Cinematográficos 13
- Off To See The Wizard Metro-Goldwyn-Mayer Animation 1
- The Off-Beats KaBlam! 1
- Ogden Entertainment 1
- Oggy Et Les Cafards Xilam Animation 195
- Ogon Bat Daiichi Dôga 52
- Ogon Senshi Gold Lightan Tatsunoko Productions 1
- Ôgon Yûsha Goldran Brave Saga 48
- Oh I Ah Soyuzmultfilm 2
- Oh Max Tundra Productions 1
- OH Productions 4
- Oh Yeah Wow Studios 1
- Oh Yeah! Cartoons Nicktoons Productions 98
- Oh, Mr Toad! Cosgrove Hall Films 13
- Oh! Family Knack Productions 1
- Oh! My Konbu Narumi 1
- Oh! Sûpâ Miruku-chan Studio Pierrot 12
- Ohayo! Spank TMS Entertainment 63
- Oi Ryoma! Animation 21 1
- Oil Can Harry TerryToons 2
- Oira Uchi no Tankofu Triangle Staff 1
- Oishinbo Shin-Ei Animation 138
- Ojamajo Doremi Tôei Company 1
- Ojamanga Yamada Kun Herald Enterprises 1
- Ojarumaru NHK 1,420
- OK K.O.! Lakewood Plaza Turbo Cartoon Network Studios 4
- Okama Hakusho Knack Productions 1
- Ôkami Shônen Ken Tôei Company 1
- Okawari Boy Starzan S Tatsunoko Productions 1
- Oki's Oasis Wild Brain 1
- Old Bear Stories Ealing Animation 41
- Old Dock Gloom International Film Service 1
- Old Lady Trio National Film Board of Canada 4
- Old Tom Millimages 52
- Olimpiada Bolka i Lolka Studio Filmów Rysunkowych 13
- Olivia Brown Bag Films 50
- Olliver's Adventures Collideascope Digital Productions 40
- Olympiad '80 Ekran 32
- Omakase Scrappers ACC Productions 1
- Ome-1 Towa Creation 1
- Omer Et Le Fils De l'Etoile Typhoon Production 26
- Omishi Mahou Gekijou Risky Safety Anime Complex II 1
- ON Animation Studios 3
- On Film 1
- Onbu Obake Eiken 52
- One and a Half Heroes Fantawild Holdings 1
- One Piece Tôei Company 1
- One Stormy Night Sparky Animation 1
- Onegai! Samia Don TMS Entertainment 1
- Onikirimaru KSS 1
- Onion Studio 1
- Oniria Pictures 2
- Ontdek de Wereld Met Nijntje Mercis Media 4
- Onyx Films 7
- Oobi Little Airplane Productions 1
- OOglies BBC 26
- Ooops! Ulysses Filmproduktion 1
- Open Alliance Media 1
- Oppidan Films 3
- Optimus Mundus EGI 50
- Opusbou 2
- Oraa Guzura Dado Tatsunoko Productions 1
- Oracle Post 7
- Orchard Pictures 1
- Ore Magi Films 7
- Ore no Sora: Deka Hen APPP 1
- Ore Wa Chokkaku Studio Pierrot 36
- Ore Wa Teppei Nippon Animation 28
- Organic Chemistry TVOntario 12
- Oriental Light and Magic 3
- Ornana Films 1
- Orson et Olivia TF1 26
- Oruchuban Ebichu Anime Ai no Awa Awa Hour 1
- Orud 2
- Oscar the Balloonist Animation Studio Ludewig 1
- Oscar's Oasis TeamTO 78
- Oscar's Orchestra Collingwood O'Hare Entertainment 39
- The Osmonds Rankin Bass Productions 17
- Osomatsu Kun Fujio Productions 114
- Osomatsu-Kun Studio Pierrot 89
- Ostankino TV Company 1
- Ostrov Sokorovisch Kievnauchfilm 2
- Oswald HIT Entertainment 52
- Oswald the Lucky Rabbit M. J. Winkler Productions 51
- Oswald the Lucky Rabbit Walter Lantz 142
- Otaku no Seiza KSS 1
- Otanoshimi Anime Gekijô Studio Zero 1
- Otenki Oneesan OB Planning 1
- Otogi Manga Calendar Otogi Productions 1
- Otogi Productions 1
- Otogi Story Tenshi No Shippo WonderFarm 1
- Otogi Zôshi Production I.G 26
- Otoko Do Ahô! Kôshien Tokyo TV Dôga 1
- Otoko Ippiki Gaki Daishô Tokyo TV Dôga 1
- Otono No Dowa Group TAC 1
- Ottifanten TFC-Trickfilmcompanie 13
- Otto Desenhos Animados 1
- Otto Luck Bray Productions 4
- Otto The Auto AAA Foundation for Traffic Safety 32
- Ottomani 1
- Ottos Ottifanten 1
- Our Football Animagrad Animation Studio 1
- Out Of Jimmy's Head Brookwell-McNamara Entertainment 20
- Out of Our Minds Images 4
- Out of the Inkwell Inkwell Studios 62
- Out Of The Inkwell Hal Seeger 100
- Out Of The Inkwell Goldwyn-Bray Pictographs 13
- Out There Television 1
- Outer Space Astronauts Russell Barrett Productions 5
- Outlaw Star Bandai Visual 25
- Oval x Over Production I.G 3
- Over The Garden Wall Cartoon Network Studios 10
- Ovide and the Gang CinéGroupe 8
- Oxfam 1
- Oy Filmkompaniet Alpha 3
- Oyoneko Boonyan Shin-Ei Animation 93
- Oyster Films 1
- Oz Madhouse Productions 1
- The Oz Kids Hyperion Pictures 1
- Ozanari Dungeon: Kaze No Tou TMS Entertainment 3
- Ozie Boo! Cyber Group Studios 3
- Ozie Boo! Protege Ta Planète Cyber Group Studios 78
- Ozu No Mahôtsukai Toho Company 52
- Ozzy & Drix Television 26