| L |
| L-HOUR | Launch Hour |
| L/I | Line Item |
| LAA | Light Antiaircraft |
| LAAM | Light Antiaircraft Missile |
| LAAT | Logistics Advisory Assistance Team |
| LAFT | Light Attack Fire Team |
| LAMPS | Light Airborne Multi-Package System |
| LANG | Language |
| LAPES | Low Altitude Parachute Extraction System |
| LARC | Lighter, Amphibious Resupply Cargo |
| LASL | Los Alamos Scientific Laboratory |
| LASR | Long An Subregion |
| LASS | Lockheed Air Services Singapore |
| LAU-17 adapters | Stub pylon on F-4. |
| LAU-3 | A rocket launcher adaptable to external bomb racks holding 19 2.75 inch air-to-ground folding fin rockets. |
| LAW | Light Antitank Weapon |
| LBN | Letter Box Number |
| Lbs | Pounds |
| LCC | Amphibious Command Ship |
| LCC | Land Clearing Company |
| LCCT | Lao Cong Chien Twon - Apprehended Deserters used as Laborers by ARVN. |
| LCM | Landing Craft Mechanized |
| LCMM | LCM Mine Sweeper |
| LCMMS | Landing Craft Mechanized, Minesweeper |
| LCOP | Logistical Control Office Pacific |
| LCP | Landing Craft, Personnel |
| LCPL | Landing Craft Personnel Light |
| LCPL | Landing Craft Personnel, Large |
| LCU | Landing Craft Utility |
| LCVP | Landing Craft Vehicle, Personnel |
| LDD | Lao Dong Dang (Lao Workers' Party) |
| LDHB | Land Development and Hamlet Building |
| LDNN | Lien Doi Nhuoi Nhai (Frogman Group/Underwater Demolition Team) VNN |
| LDNN | SEAL Support Ships |
| LDP | Logistics Development Plan |
| LDPC | Logistical Data Processing Center |
| LEI | Life Extension Inspection |
| Leverage | The use of resources in such a manner that action is initiated or that a greater result is achieved with minimum input of effort. |
| LF | Local Force |
| LF | Low Frequency |
| LFT | Light Fire Team |
| LGB | Laser Guided Bomb |
| LHFT | Light Helicopter Fire Team |
| LIB | Light Infantry Brigade |
| Lien Doi | Regional Force Company Group |
| Lien Viet | Full title - Mat-tran Lien Viet Quoc Dan Viet-Nam United Vietnamese Nationalist Front organization formed on May 27, 1946 which became the political organizational structure for the Viet-Minh. It was considered a popular (nationalist) front party in North Vietnam and eventually outlived its usefulness as an organizational vehicle for the North Vietnamese communists. |
| LIMDIS | Limited Distribution |
| LKA | Amphibious Cargo Ship |
| LLDB | Vietnamese Special Forces |
| LLLTV | Low Light Level Television |
| LM | Legion of Merit |
| LMAT | Logistics Management Assistance Team, Inc. |
| LN | Local National(s) |
| Lnd | Land |
| LnO | Liaison Officer |
| LNO | Liaison Officer |
| LNRS | Limited Night Recovery System |
| LO | Liaison Officer |
| LOC | Line(s) of Communication |
| LOCC | Logistical Operations Control Center |
| LOCC | Logistics Offensive Coordination Committee |
| Log | Logistics; Logistical |
| LOG CMD | Logistical Command |
| Log Comd | Logistical Command |
| LOG MGT | Logistics Management |
| LOGAIR | Air Logistics |
| LOH | Light Observation Helicopter |
| LOI | Letter of Instruction |
| Loose Deuce | Term to describe fighter tactics in which two to four airplanes maneuver to provide mutual support and increased fire power. |
| LORAN | Long Range Airborne Navigation |
| LOTS | Logistic-Over-the-Shore |
| LOU | Limited Official Use |
| LOX | Liquid Oxygen |
| LP | Listening Post |
| LPA | Amphibious Transport |
| LPA | Liberation Press Agency |
| LPD | Landing Platform, Dock |
| LPF | Lao Patriotic Front |
| LPH | Landing Platform, Helicopter/Amphibious Assault Ship |
| LQM | Link Quality Monitor |
| LRC | Logistics Readiness Center |
| LRP | Long Range Patrol |
| LRRP | Long Range Reconnaissance Patrol |
| LS | Liaison Service |
| LS | Lima Site |
| LSAD | Liaison Service Advisory Detachment |
| LSB | Logistics Support Base/Branch |
| LSB/ISB | Logistics Support Base/Intermediate Support Dase |
| LSD | Landing Ship Dock |
| LSI | Lear Siegler Incorporated |
| LSIL | Landing Ship Infantry, Large |
| LSIL | Landing Ship Infantry, Light |
| LSM | Landing Ship, Medium |
| LSM(H) | Landing Ship Medium, Hospital |
| LSM-H | Landing Ship, Medium - Hospital |
| LSM/H | Landing Ship Hospital |
| LSMR | Landing Ship Medium Rocket |
| LSSC | Light SEAL Support Craft |
| LSSL | Landing Ship, Support, Large |
| LST | Landing Ship, Tank |
| LT | Lieutenant |
| LT INF | Light Infantry |
| LTC/LTCOL | Lieutenant Colonel |
| LTD | Language Training Detachment |
| LTG | Lieutenant General |
| LTJG | Lieutenant Junior Grade |
| LTL | Lien Tinh Lo (Interprovincial Highway) |
| LTR | Letter |
| Luc Luong | Kit Carson Scouts |
| Lufberry circle | A circular tail chase, ascending or descending. |
| LVT | Landing Vehicle Track |
| LVTC | Landing Whicle Tracked Command |
| LVTP | Landing Vehicle Tracked Personnel |
| LZ | Landing Zone |