Computer file extensions - O

Updated: 12/26/2023 by Computer Hope

Below is a listing of each of the different file extensions that begin with the letter "O." If you are looking for a file extension that starts with a different letter, click the corresponding beginning letter below.

.OBJ Universal format for 3-D models, textures, materials, and associated data.
.OCA Control typelib cache.
.OCX OLE (Object Linking and Embedding) control extension.
.ODT Document file created in LibreOffice and OpenOffice Writer word processor program.
.OGA OGG OggPCM or Vorbis sound file.
.OGG OGG OggPCM or Vorbis sound file.
OGG OggUVS, Tarkin, or Theora video file.
OGG Annodex, CMML, OggKate, or Writ text file.
.OGM An Ogg Media File, OGM files are movie files.
.OGV OGG Tarkin or Theora video file.
.OLB Object library.
.OLD Used for backups of important files in case they are improperly updated or deleted.
.OLE Object Linking and Embedding object file.
.OLI Olivetti text file.
.OPUS OGG Opus sound file.
.ORF Digital camera RAW file format.
.ORI Original file.
.OST A Microsoft Outlook offline data file.
.OTL A Z-soft type foundry font file and other program files template file.
.OVA Archive file containing files for virtualization software, like VMware Workstation.
.OXPS Document file created using the Microsoft open XPS (XML Paper Specification) format.