- LUTS
- LVDS
- LVDT
- LVH
- LVL
- LVQ
- LVRT
- LWD
- LWE
- LWR
- LXC
- LXI
- LXR
- LZ77
- LZMA
- LZSS
- LZW
- La Crosse encephalitis
- LaSalle's invariance principle
- Lab frame
- Lab-on-a-chip
- LabVIEW
- Labdane
- Label switching
- Labeled data
- Labeling
- Labelling
- Labels
- Labile
- Lability
- Labor market
- Laboratory
- Laboratory automation
- Laboratory flasks
- Laboratory glassware
- Laboratory quality control
- Labral
- Labyrinth seals
- Lac operon
- Lac repressor
- Laccase
- Laccoliths
- Lachman test
- Lacquer
- Lacquer thinner
- Lacrimal gland
- Lacrimal punctum
- Lacrimal sac
- Lactalbumin
- Lactaldehyde
- Lactams
- Lactase
- Lactate dehydrogenase
- Lactation
- Lactic acid
- Lactic acid bacteria
- Lactic acid fermentation
- Lactic acidosis
- Lactide
- Lactobacillaceae
- Lactobacilli
- Lactobacillus acidophilus
- Lactobacillus brevis
- Lactobacillus bulgaricus
- Lactobacillus casei
- Lactobacillus delbrueckii
- Lactobacillus fermentum
- Lactobacillus plantarum
- Lactobacillus rhamnosus
- Lactobacillus salivarius
- Lactobionic acid
- Lactococcus lactis
- Lactoferrin
- Lactonase
- Lactones
- Lactoperoxidase
- Lactose intolerance
- Lactulose
- Lacunae
- Lacunarity
- Lacustrine
- Lacustrine deposits
- Lacustrine plain
- Ladder
- Ladder logic
- Ladder operators
- Ladder topology
- Ladle
- Lag3
- Lagoon
- Lagrange interpolation
- Lagrange multiplier
- Lagrange points
- Lagrange polynomial
- Lagrangian
- Lagrangian particle tracking
- Lagrangian points
- Lagrangian relaxation
- Lagrangian system
- Lahars