| File extension | The full name of the file |
|---|---|
| File extension O | Object Format |
| File extension O01 | Typhoon Voice |
| File extension O2C | Objects To See 3D |
| File extension O8D | OCTGN Deck |
| File extension O8G | OCTGN Game Definition |
| File extension O8O | Mediator 5 Repository Tabs Vorlagen.006 |
| File extension O8S | OCTGN Set |
| File extension OAB | Microsoft Outlook Offline Address Book Format |
| File extension OAD | Suite Notaro Document |
| File extension OAF | Microsoft Flight Simulator Texture |
| File extension OAM | Adobe Edge Overlay Format |
| File extension OAP | Samsung Bada Signed Installation Package |
| File extension OAR | OpenSimulator Archive Format |
| File extension OAS | Microsoft Outlook Attachment Sniffer |
| File extension OAT | Google Android RunTime Code |
| File extension OAV | Microsoft Flight Simulator Texture |
| File extension OAW | OpenArchitectureWare Workflow |
| File extension OAZ | NetFax Manager OAZ Fax Image |
| File extension OB | IBM LinkWay Object |
| File extension OB! | Orbit Downloader Incomplete Download Format |
| File extension OB3 | ABF Software Outlook Backup Backup |
| File extension OB5 | TopLang OE Backup |
| File extension OBAK | WinSQL Offline Backup |
| File extension OBB | Google Android Opaque Binary Blob Format |
| File extension OBD | Microsoft Office Binder Document Format |
| File extension OBF | OsmAnd Offline GPS Vector Maps |
| File extension OBG | ZBrush Mesh |
| File extension OBI | Microsoft Outlook 2007/2010/2013 RSS Subscription Format |
| File extension OBJ | 3D Object Format |
| File extension OBJX | Metatools Object Bryce Support |
| File extension OBK | OrCAD Capture Design Or Library |
| File extension OBL | TrueSpace |
| File extension OBML | Opera Mini Saved Web Page Format |
| File extension OBML15 | Opera Mini 5.1 Saved Web Page |
| File extension OBP | Bryce Object Format |
| File extension OBPACK | ObjectBar Theme Pack |
| File extension OBR | Borland C++ Object Browser Data |
| File extension OBS | WAsP Obstacle List |
| File extension OBT | Openbox Theme Format |
| File extension OBV | 3D Photo Browser Thumbnail Cache |
| File extension OBW | Toontrack Superior Drummer Audio Format |
| File extension OBX | Rational XDE |
| File extension OBYX | Obyx Control |
| File extension OBZ | Compressed 3D Object Format |
| File extension OC3 | OpenCanvas 3 Event Format |
| File extension OC4 | OpenCanvas 4 Event Format |
| File extension OC5 | OpenCanvas 5 Event Format |
| File extension OC9 | OrgCon Organization |
| File extension OCA | Custom Control Library Type Format |
| File extension OCAMLMAKEFILE | Caml Programming Language Makefile |
| File extension OCB | Origin Precompiled Origin C |
| File extension OCC | Oceanic DataPool Format |
| File extension OCD | OCAD Digitized Map Format |
| File extension OCDC | Mathematica Document |
| File extension OCDF | OneClickDigital Mp3 Audio Book |
| File extension OCE | Open Catalog Extension Connection Format |
| File extension OCEN | EdGCM Data |
| File extension OCF | OM2 Cipher |
| File extension OCG | Osprey Custom Graph |
| File extension OCI | OpenCanvas Image Format |
| File extension OCM | Netscape Communicator Aim |
| File extension OCP | Advanced Art Studio Image |
| File extension OCR | FaxGrapper FAX Transcribed Text Format |
| File extension OCT | RADIANCE Octree Format |
| File extension OCTEST | Xcode Objective-C Unit Test Bundle |
| File extension OCV | OCV Training Data |
| File extension OCX | ActiveX Control Format |
| File extension OC_ | Compressed ActiveX Control |
| File extension OD | Mascotte Mascopt Request Format |
| File extension OD1 | Omnis 5 Database |
| File extension OD2 | Omnis 5 Database |
| File extension OD3 | Omnis Studio Database |
| File extension OD4-9 | Omnis5 Database |
| File extension ODB | ArcView Object Database ASCII Format |
| File extension ODC | OpenOffice.org OpenDocument Format |
| File extension ODCCUBEFILE | OpenDocument 1 |
| File extension ODCNEWFILE | Microsoft Office Data Connection |
| File extension ODCTABLEFILE | Microsoft Office |
| File extension ODE | Microsoft Office |
| File extension ODEX | Google Android Optimized Executalbe |
| File extension ODF | Open Document Interchange Format (ODIF) |
| File extension ODG | OpenDocument Drawing Format |
| File extension ODH | Microsoft Visual Studio Interface Definition Language |
| File extension ODI | OpenOffice.org Image Format |
| File extension ODIF | Open Document Interchange Format |
| File extension ODL | Object Description Language Format |
| File extension ODM | OpenOffice.org OpenDocument Global Text Document Format |
| File extension ODO | ICUBE Online Operating System Write Document Format |
| File extension ODP | OpenOffice.org OpenDocument Presentation Format |
| File extension ODS | OpenDocument Spreadsheet Format |
| File extension ODT | ODF Text Document Format |
| File extension ODT# | OpenOffice.org Locked Document |
| File extension ODTPC | Oracle User Productivity Kit Presentation |
| File extension ODTTF | Microsoft Office Document Embedded Font |
| File extension ODV | Ocean Data View Data |
| File extension ODVI | LaTeX |
| File extension ODX | Microsoft BizTalk Server Diagram Format |
| File extension OD_ | Oracle Compressed Driver |
| File extension OEACCAOUNT | Windows Mail |
| File extension OEACCOUNT | Windows Mail Account Settings Format |
| File extension OEB | Open EBook Format |
| File extension OECL | Open EDA Component Library |
| File extension OEF | Optim Export |
| File extension OEM | OEM Install Data Format |
| File extension OEMIGACCOUNT | Outlook Express Temporary |
| File extension OET | ESignal Order Entry Ticket |
| File extension OEX | Opera Add-on Format |
| File extension OFA | Kodak OfotoNow |
| File extension OFB | Oxygen Forensic Suite Backup |
| File extension OFC | Open Financial Connectivity Format |
| File extension OFD |
File extensions in alphabetical order: O
The list of file extensions, sorted alphabetically, beginning with the letter O