| K | Potassium |
| Ka-band | 20-30 GHz (broadband) |
| KB | Kilo Bytes |
| KDC | Kodak Digital Camera image format |
| KDLOC | 1000 Developed source Lines Of Code |
| keV | Kilo Electron Volt |
| KGB | Known Good Board |
| KGD | Known Good Die |
| kilo | 1.00E+3 (1,000/1; symbolized by the prefix k) |
| KIT | Key Intelligence Topics; Kingston Interactive Television |
| KLV | Key, Length, Value data encoding protocol (SMPTE 336M) |
| KPA | Key-Process Area |
| Kr | Krypton |
| KSLOC | 1000 source lines of code |
| Ku-band | Satellite to Satellite communication frequency (10.9-17 GHz) |
| kV | KiloVolt |
| KVM | Keyboard, Video, Mouse (switch) |
| La | Lanthanum |
| LAMMA | LAser Microprobe Mass Analysis |
| LAMMS | LAser Micro-Mass Spectroscopy |
| LAN | Local Area Network |
| LANL | Los Alamos National Laboratory |
| LAR | Lot Age Report |
| LASER | Light Amplification by Stimulated Emission of Radiation |
| LBM | Deluxe Paint image format |
| LC | Inductance-capacitance; Liquid Chromatography |
| LCA | Life-Cycle Analysis |
| LCAO | Linear Combination of Atomic Orbitals |
| LCAS | Line Card Access Switch |
| LCC | Leaded Chip Carrier |
| LCCC | Leadless Ceramic Chip Carrier |
| LCD | Liquid Crystal Display |
| LCL | Lower Confidence Limit |
| LD | Laser Diode |
| LDA | Local Density Approximation; Logic design automation |
| LDAP | Lightweight Directory Access Protocol |
| LDD | Lightly Doped Drain |
| LDDM | Laser Doppler Displacement Meter |
| LDL | Lower Detection Limit |
| LDMOS | Latterally Diffused MOS |
| LDOS | Local Density Of States |
| LDP | Low Density Plasma |
| LDPE | Low Density PolyEthylene |
| LDSD | Low Dimensional Structures & Devices |
| LEC | Liquid Encapsulation Czochralski |
| LED | Light-Emitting Diode |
| LEED | Low-Energy Electron Diffraction |
| LEIS | Low Energy Ion Scattering |
| LEL | Lower Explosive Limit |
| LEP | Light Emitting Polymer |
| LEP | Light Emitting Polymer |
| LER | Lissajous Electron Plasma |
| LF | Laminar Flow |
| LFL | Lower Flammable Limit |
| LFT | Ligand-Field Theory |
| LGE | Light Generation Efficiency |
| LGQ | Linear Gaussian quadratic |
| Li | Lithium |
| LI | Laser Interferometry |
| LIC | Linear Integrated Circuit |
| LID | Leadless Inverted Device |
| LIDAR | LIght Detection And Ranging technology |
| LIF | Low Insertion Force |
| LIFO | Last In, First Out |
| LIMA | Laser-Induced Mass Analysis |
| LIMS | Laser-Induced Mass Spectrometry |
| LIR | Location Inventory Report |
| LJ | Lennard Jones (potential) |
| LKDM | Low k Dielectric Material |
| LLCC | Leadless Chip Carrier |
| LLD | Lower Limit of Detection |
| LLM | Local Linear Models |
| LLNL | Lawrence Livermore National Laboratory |
| LLNQ | Least Lots Next Queue |
| LLR | Large Lattice Relaxation |
| LLS | Localized Light Scatterer |
| LM | Light Microscopy |
| LMC | Least Material Condition |
| LMMA | Laser Microprobe Mass Analysis |
| LMTO | Linear Muffin-Tin Orbital |
| LN | Liquid Nitrogen (temperature) |
| LNA | Low Noise Amplifier |
| LNDF | Linear Natural Density Filter |
| LO | Local Oscillator |
| LOC | Level Of Concern |
| LOCOS | LOCal Oxidation of Silicon |
| LOI | Letter Of Intent |
| LOS | Loss Of Selectivity |
| LP | Local Pair |
| LPC | Linear Predictive Coding; Laser Particle Counter; Low Particle Concentration; Liquid-borne Particle Counter |
| LPCVD | Liquid Phase Chemical Vapour Deposition; Low Pressure CVD |
| LPD | Light Point Defect; Laser Projection Display |
| LPE | Liquid Phase Epitaxy |
| LPI | Low-Pressure Isolation |
| LPISM | Liquid Photo-Imageable Solder Mask |
| LPSM | Levenson Phase Shift Mask |
| LPV | Low-Pressure Vent |
| Lr | Lawrencium |
| LRP | Long Range Plan |
| LRS | Laser Raman Spectroscopy |
| LRU | Lowest Replaceable Unit |
| LS | Low-power Schottky |
| LSB | Least Significant Bit |
| LSE | Latex Sphere Equivalent |
| LSHI | Large-Scale Hybrid Integration |
| LSI | Large-Scale Integration |
| LSM | Laser Scanning Microscope |
| LTC | Lithographic Test Chip |