- T-WWIN
- Tactical Wideband Wireless Network
- TacSat
- Tactical Microsatellite Experiment
- TAG
- Technical Advisory Group
- TCB
- Trusted Computing Base
- TCDS
- Tactical Cross Domain Solution
- TCG®
- Trusted Computing Group®
- TCO
- Total Cost of Ownership
- TCP
- Transmission Control Protocol
- TCSEC
- Trusted Computer Security Evaluation Criteria
- TDO
- Theory of Design and Operation
- TEE
- Trusted Embedded Environment
- TEK
- Traffic Encryption Key
- TELCO
- Telephone Company
- TES-LITE
- Tactical Exploitation System
- TFM
- Trusted Facility Manual
- TFS
- Traffic Flow Security
- TKMS
- Tactical Key Management System
- TL
- TACLANE
- TLS
- Transport Layer Security
- TMA
- Technology Maturity Assessment
- TNC
- Trusted Network Connect
- TNE
- Trusted Network Environment
- TOC
- Theory of Compliance
- TOD
- Time of Day
- TOH
- Transport Overhead Header
- Top Secret SA
- Special Access (compartmented)
- ToS
- Type of Service
- TPM
- Trusted Platform Module
- TRANSEC
- Transmission Security
- TRL
- Technology Readiness Level
- TS
- Top Secret
- TS/SCI
- Top Secret/Special Compartmentalized Information
- TSAT
- Transformational Satellite Communication System
- TSE
- Trusted Security Engine
- TT&C
- Telemetry, Tracking and Command
- TV
- Tamper Vector
- TVE
- Trusted Virtual Environment
- Tx/Rx
- Transmitter/Receiver
- U
- Unclassified
- UAS
- User Application Software
- UAV
- Unmanned Aerial Vehicles
- UCDMO
- Unified Cross Domain Management Office
- UDP
- User Data Protocol; a part of basic Internet Protocol (IP)
- UFL2.06
- UltraFASTLANE Release 2.06
- UFL2.1
- UltraFASTLANE Release 2.1
- UFL2.2
- UltraFASTLANE Release 2.2
- UL
- Underwriter Laboratories
- UMTS
- Universal Mobile Telecommunications System
- UNI
- User Network Interface
- UR
- User Representative
- USA
- United States of America
- USB
- Universal Serial Bus
- uSec
- microseconds
- v
- Version
- VAC
- Volts, Alternating Currents
- VAST
- Vehicle Analysis and Simulation Tool
- VBR
- Variable Bit Rate
- VCI
- Virtual Channel Identifier
- VDC
- Volts Direct Current
- VLAN
- Virtual Local Area Network
- VLSI
- Very Large-Scale Integration
- VM
- Virtual Machines
- VME
- Versa Module Europa
- VMOC
- Virtual Mission Operations Center
- VoIP
- Voice over Internet Protocol
- VoSIP
- Voice over Secure IP
- VPN
- Virtual Private Network
- VPNs
- Virtual Private Network - is a communications network tunneled through another network, and dedicated for a specific network.
- VRRP
- Virtual Router Redundancy Protocol
- VTC
- Video Teleconference
- WAN
- Wide Area Network
- WED
- Windtalker Encryption Device
- WGS
- Wideband Global SATCOM; Wideband Gapfiller Satellite system
- WI FI
- Wireless Fidelity
- WIN-T
- Warfighter Information Network Tactical
- Wireline Terminals
- Compact, lightweight, portable devices that connect to a standard desktop analogue phone or personal computer. These encryption devices can be used in a stationary environment or can be transported to remote or temporary locations.
- WITS
- Wireless Information Transfer System
- WRED
- Weighted Random Early Detection
- XML
- eXtensible Markup Language
- XMT
- Transmit