| Map | Title | Author | Players | |
|---|---|---|---|---|
| CTF-OA-BRING_IT_2003 | OA-BRING_IT_2003 "OPPOSITES ATTRACT" | STATIC3D | 10-16 | |
| CTF-Oblivion | Oblivion Cargo Freighter | MsM | 8 | |
| CTF-OldCitySubway | Old-City-Subway | KhanArtist | 4-6 | |
| CTF-OldSkoolHallz-v1-0 | The Old Skool Hallz | Sam 'Syphir' Jones | 8-12 | |
| CTF-Omaha_Beach | CTF-Omaha_Beach | W@RLOCK | 10 | |
| CTF-OmegaFacility | Omega Facility | Karl "Commander Cool" Hahn | 10-16 | |
| CTF-Ominous | Ominous Moon 2K3 | SiR_CharLZ | 8-16 | |
| CTF-Oraxin | Oraxin Installation | Nicholas 'CyMek' Richards | 8-14 | |
| CTF-Orb2K3[Rev1] | CTF-Orb2K3 | KillBait! (UT2K3) - Squacky (UT) | 8-12 | |
| CTF-Orb_1 | CTF-ORB_1_C13 | Stephen Mark Huish | Unknown | |
| CTF-Orbital | CTF-Orbital | Unknown | Unknown | |
| CTF-Orbital-Classic2k3 | Orbital Classic 2003 | [VF]Strawa | Unknown | |
| CTF-OrionStation-BETA | Orion Station | Abyss | 8-16 | |
| CTF-Osiris2 | BR - Osiris Revision 2 | Antti "Zimeon" Hurme | 16 | |
| CTF-Outlook2K3SE | Outlook][K3_SE | SiR CharLZ | 8-16 | |
| CTF-Outpost-33 | Outpost #33 | Xlucifer | 10-16 | |
| CTF_optimal_warfareVER2 | Optimal Warfare | |:chapt0r1:| OpTimaL | 8 |