| OAD Rain | Generate | 2009-2013 |
| Oak | Fat Cat | |
| Oak & Linden | Pat Barett | 2009 |
| Oaky Doaks | Eastern Color | 1942 |
| Oasis | Alex Wills | |
| Oates & the Elphyne, The | Humanoids | 2022 |
| Oatmeal | Blind Bat | 1994, 1996 |
| Oatmeal Journal | Oatmeal | 1995-1996 |
| Oba Electroplating Factory | Drawn & Quarterly | 2024 |
| Obama: Inaugural Edition | Antarctic | 2009 |
| Obama Story, The | Dasan | 2009 |
| Obama: The Comic Book | Antarctic | 2008 |
| Obamouse | Antarctic | 2010 |
| OBE | Antarctic | 2021 |
| Obedient One | Icarus | 2009 |
| Obergeist: Ragnarok Highway | Image | 2001 |
| Obergeist: The Empty Locket | Image | 2002 |
| Oberon | AfterShock | 2019 |
| Obey Me | Dynamite | 2019 |
| Obey Me the Comic | Seven Seas | 2023 |
| Obie | Store | 1953 |
| Obi-Wan And Anakin | Marvel | 2016 |
| Object 15: Works by Kilian Eng | Alternative | 2016 |
| Objective Five | Image | 2000-2001 |
| Object of Desire | Aurora | 2008 |
| Object Of My Affection | Digital Manga | 2010 |
| Obliv18n | Scout | 2018 |
| Oblivion | COMICO | 1995-1996 |
| Oblivion (Action Lab) | Action Lab | 2016 |
| Oblivion (Considerable) | Considerable Comics | 1990 |
| Oblivion (Radical) | Radical | 2010 |
| Oblivion City | Slave Labor | 1991-1992 |
| Oblivion Rouge | Saturday AM | 2023 |
| Oblivion Song | Image | 2018-2022 |
| Oblivion Trials, The | Source Point | 2022 |
| Obnoxio the Clown | Marvel | 1983 |
| Obnoxio the Clown (Canadian Edition) | Marvel | 1983 |
| Obnoxious Hero-kun | Seven Seas | 2023 |
| Obscure | Obscure | 1985 |
| Obscure Cities, The: The Return of Captain Nemo | Alaxis | 2024 |
| Obscurity Unlimited’s Ad Book | Dimestore | 2003 |
| Observable | Actus Tragicus | 1998 |
| Obsession | Heavy Metal | 1996 |
| Obsession: A Graphic Novel | Heavy Proton | 2008 |
| Obsoletes, The | Silverline | 2023 |
| OBS: Vampirsoldat | Evoluzione | 2022 |
| Oca, La | Editorial Ipanema | 1985 |
| O Caminho das Estrelas | Agência Portuguesa de Revistas | 1978 |
| Occult Crimes Taskforce | Image | 2006 |
| Occulted | Iron Circus | 2023 |
| Occult Files of Dr. Spektor, The | Gold Key | 1973-1977, 1982 |
| Occult Generation: Prelude | Studio OG | 2016 |
| Occultic Nine | Seven Seas | 2017-2018 |
| Occultist, The | Dark Horse | 2010 |
| Occultist, The (2nd Series) | Dark Horse | 2011 |
| Occultist, The (3rd Series) | Dark Horse | 2013 |
| Occultist Omnibus, The | Dark Horse | 2018 |
| Occult Laff-Parade | Print Mint | 1973 |
| Occult Presence | Floating World | 2024 |
| Occupational Hazards | CD | 2000 |
| Occupy Avengers | Marvel | 2017 |
| Occupy Comics | Black Mask | 2013 |
| Ocean | WildStorm | 2004–2005, 2010 |
| Ocean Comics | Ocean | |
| Ocean Master: Year of the Villain | DC | 2020 |
| Ocean of Secrets | Tokyopop | 2018 |
| Ocean Smoke | Submarine Treehouse | 2024 |
| Oceanus: Act One | FutureDude | 2015 |
| Oceanverse | Oceanverse | 2009 |
| Ocean Will Take Us, The | AfterShock | 2022 |
| Ocelot, The | Eros | 1994 |
| Ochlocrat, The | Comics Conspiracy | |
| Ocho: Kill The Blue Man | Eric Mengel | 2010 |
| OCSA Comics | Invader | 2022 |
| Octavia | Antimatter | 2004-2005 |
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