- Labyrinth spider
- Lace Monitor
- Ladder-backed Hover Fly
- Ladder-backed Woodpecker
- Lancet Clubtail
- Lang's Short-tailed Blue
- Lapland Longspur
- Larder Beetle
- Large Conehead
- Large Copper
- Large Lace-border Moth
- Large Maple Spanworm Moth
- Large Milkweed Bug
- Large Mossy Glyph
- Large Orange Sulphur
- Large Psammodromus
- Large Red Damselfly
- Large Skipper
- Large Spotted Ladybird
- Large Tortoiseshell
- Large Wall Brown
- Large White
- Large Yellow Underwing
- Large-billed Crow
- Large-tailed Aphideater
- Largemouth Bass
- Lark Sparrow
- LaTouche's Frog
- Latticed Heath
- Laughing Dove
- Laughing Gull
- Laughing Kookaburra
- Lazuli Bunting
- Leafhopper Assassin Bug
- Leafy Spurge Hawkmoth
- Least Carpet
- Least Flycatcher
- Least Grebe
- Least Sandpiper
- Least Skipper
- Leather Beetle
- Leather Star
- Leconte's Haploa Moth
- Lemon Cuckoo Bumble Bee
- Lemon Migrant
- Lemon Pansy
- Leopard Slug
- Leopard Tortoise
- Leptoglossus oppositus
- Leptoglossus zonatus
- Lesser Black-backed Gull
- Lesser Emperor
- Lesser Goldfinch
- Lesser Grass Blue
- Lesser Hornet Hoverfly
- Lesser Maple Spanworm Moth
- Lesser Marbled Fritillary
- Lesser Purple Emperor
- Lesser Scaup
- Lesser Spotted Woodpecker
- Lesser Stag Beetle
- Lesser Whitethroat
- Lesser Yellow Underwing
- Lesser Yellowlegs
- Lesson's Motmot
- Leucauge argyra
- Lewes Wave
- Lewin's Honeyeater
- Ligated Furrow Bee
- Light Brown Apple Moth
- Light Emerald
- Light-vented Bulbul
- Lily Leaf Beetle
- Lime Hawkmoth
- Lime seed bug
- Lime Swallowtail
- Lime-speck Pug
- Limpkin
- Lincoln's Sparrow
- Lineated Woodpecker
- Little Black Cormorant
- Little Blue Heron
- Little Brown Skink
- Little Corella
- Little Cormorant
- Little Egret
- Little Glassywing
- Little Grebe
- Little grey
- Little Gull
- Little Heron
- Little Owl
- Little Pied Cormorant
- Little Ringed Plover
- Little Stint
- Little Tern
- Little Wattlebird
- Little Wood Satyr
- Little Yellow
- Locust Borer
- Loggerhead Shrike
- Lone Star Tick
- Long Dash
- Long-billed Corella
- Long-billed Curlew
- Long-billed Dowitcher
- Long-bodied Cellar Spider
- Long-claw Hermit Crab
- Long-eared Owl
- Long-legged Tabby
- Long-necked Seed Bug
- Long-nosed Fur Seal
- Long-tailed Duck
- Long-tailed Rosefinch
- Long-tailed Shrike
- Long-tailed Skipper
- Long-tailed Tit
- Long-winged Conehead
- Longhorn Crazy Ant
- Lorquin's Admiral
- Louisiana Waterthrush
- Lucerne Moth
- Lunate Zale Moth
- Lyside Sulphur