- COMMARFORNORTH (COMmander, MARine Corps FORces North)
- COMMARFORSOC (Commander, U.S. Marine Corps Forces Special Operations Command)
- COMMDZ (COMmander, Maritime Defense Zone)
- COMMIT (Connecting Opportunities To Motivate Mend And Intervene For Teens)
- COMMO (COMMunications Officer)
- Comm. Prec. (Commemoratio Praecedentis ("Commemoration of the preceding feast" Breviary))
- Comm. Seq. (Commemoratio Sequentis ("Commemoration of the following feast" Breviary))
- COMMZ (Communications Zone (military))
- COMNAV (Committee for European Airspace Coordination Working Group on COMmunications and NAVigation Aids)
- COMNAVAIRFOR (COMmander, NAVal AIR FORces)
- COMNAVAIRLANT (COMmander, NAVal AIR forces, atLANTic)
- COMNAVAIRPAC (COMmander, NAVal AIR forces, PACific)
- COMNAVAIRSYSCOM (COMmander, NAVal AIR SYStems COMmand)
- COMNAVCOMTELCOM (COMmander, NAVal COMputer and TELecommunications COMmand)
- COMNAVELEXSYSCOM (COMmander NAVal ELEctronics SYStems COMmand)
- COMNAVFOR (COMmander, NAVy FORces)
- COMNAVMETOCCOM (COMmander, NAVal METeorology and OCeanography COMmand)
- COMNAVSEACOMBATSYSENGSTA (COMmander, NAVal SEA COMBAT SYStems ENGineering STAtion)
- COMNAVSEASYSCOM (COMmander, NAVal SEA SYStems COMmand)
- COMNAVSECGRP (COMmander, United States NAVy SECurity GRouP)
- COMNAVSECGRU (COMmander, NAVal SECurity GRoUp)
- COMNAVSURFLANT (COMmander, NAVal SURface Force, AtLANTic)
- COMNAVSURFPAC (COMmander, NAVal SURface Force, PACific)
- COMO (Computer Model)
- Comp (B Composition B)
- COMPACAF (COMmander, PACific Air Forces)
- COMPACAREACOGARD (COMmander, Coast Guard PACific AREA)
- COMPACFLT (COMmander, PACific FLeeT (formerly CINCPACFLT))
- COMPACT (COMmittee to Preserve American Color Television)
- COMPARE (Citizens Opposing the Megamall and Proposed Access Road Extension)
- COMPAS (Curriculum-Oriented Mathematics Placement for Academic Success)
- COMPASS (Community Organisations Management Planning And Support Services)
- COMPED (COMPensatory EDucation)
- COMPES (Contingency Operations Mobility Planning and Execution System)
- Compl. (Completorium ("Compline" Breviary))