- Tailed Jay
- Taiwan Japalure
- Tan Jumping Spider
- Tapered Drone Fly
- Tau Emerald
- Tawny Coster
- Tawny Emperor
- Tawny Frogmouth
- Tawny Mining Bee
- Tawny Owl
- Tawny-edged Skipper
- Temminck's Stint
- Tennessee Warbler
- Tersa Sphinx
- Tessellated Water Snake
- Texan Crescent
- Texas Brown Tarantula
- Texas Cooter
- Texas Gray
- Texas Spiny Lizard
- The Chestnut
- The Flame
- The Lackey
- The Passenger
- The Snout
- The Tanner
- The White-Point
- Thick-legged Flower Beetle
- Thick-legged Hover Fly
- Thin-shelled Rock Crab
- Thistle Stem Gall Fly
- Thoas Swallowtail
- Threadfin Butterflyfish
- Three Spotted Nettle Bug
- Threespine Stickleback
- Thrush Nightingale
- Tidepool Sculpin
- Tiger Bee Fly
- Tiger Spider
- Tigrosa annexa
- Tiny Grass Blue
- Tokay Gecko
- Topiary Grass-veneer
- Tortoise Bug
- Townsend's Solitaire
- Townsend's Warbler
- Transcaucasian Giant Mantis
- Transverse-banded Flower Fly
- Treble Lines
- Tree Bumble Bee
- Tree Pipit
- Tree Swallow
- Triangle Crab Spider
- Triangulate Combfoot
- Tricolored Bumble Bee
- Tricolored Heron
- Trivittate Marsh Fly
- Tropical Checkered-Skipper
- Tropical Fritillary
- Tropical House Cricket
- Tropical House Gecko
- Tropical Kingbird
- Tropical Mockingbird
- Tropical Tent-web Spider
- Trumpeter Swan
- Tufted Duck
- Tufted Titmouse
- Tule Bluet
- Tulip-tree Beauty
- Tundra Swan
- Turkey Vulture
- Turkish Snail
- Turnip Moth
- Turnip Sawfly
- Turquoise-browed Motmot
- Twelve-spotted Skimmer
- Twenty-spotted Lady Beetle
- Twice-stabbed Stink Bug
- Twin-flagged Jumping Spider
- Twister
- Two-lined Leatherwing
- Two-lined Spittlebug
- Two-spotted Bumble Bee
- Two-spotted Grass Bug
- Two-spotted Lady Beetle
- Two-spotted Longhorn Bee
- Two-spotted Tree Cricket
- Two-striped Grasshopper
- Two-tailed Swallowtail