| Company |
City |
State |
| Tahoe Regional Planning Agency | Stateline | Nevada |
| Tallgrass Restoration, LLC | Schaumburg | Illinois |
| TBE Group Inc | Clearwater | Florida |
| TEC Inc. | Charlottesville | Virginia |
| TechnoServe | Kigali | International |
| Techsea International, Inc. | Seattle | Washington |
| Tekna Milano | Crescentville | Georgia |
| TerraMai | McCloud | California |
| TerraMai | McCloud | California |
| Teton Science Schools | Jackson | Wyoming |
| Tetra Tech EC, Inc. | Morris Plains | New Jersey |
| Tetra Tech EC, Inc. | Morris Plains | New Jersey |
| Tetra Tech FW | Santa Ana | California |
| The Centre for Australian Weather and Climate Research | Clayton, VIC, Australia | International |
| The Charles Stark Draper Laboratory, Inc. | Cambridge | Massachusetts |
| The Climate Registry | Los Angeles | California |
| The College Settlement Outdoor School | Horshma | Pennsylvania |
| The Conservation Fund | Arlington | Virginia |
| The Epsten Group, Inc. | Atlanta | Georgia |
| The Everglades Foundation | West Palm Beach | Florida |
| The International Council on Clean Transportation | Washington | District of Columbia |
| The Louis Berger Group, Inc | Morristown | New Jersey |
| The LPA Group Inc. | Columbia | South Carolina |
| THE LPA GROUP INCORPORATED | Columbia | South Carolina |
| The Nature Conservancy | Arlington | Virginia |
| The Nature Conservancy | Arlington | Virginia |
| The Nature Conservancy | Arlington | Virginia |
| The Nature Conservancy - Alaska | Anchorage | Alaska |
| The Nature Conservancy - Florida | Altamonte Springs | Florida |
| The Nature Conservancy - Illinois | Peoria | Illinois |
| The Nature Conservancy - Kansas | Topeka | Kansas |
| The Nature Conservancy - Massachusetts | Northampton | Massachusetts |
| The Nature Conservancy - Michigan | Lansing | Michigan |
| The Nature Conservancy - Minnesota | Minneapolis | Minnesota |
| The Nature Conservancy - Northern California | San Franicisco | California |
| The Nature Conservancy - Northern California | San Franicisco | California |
| The Nature Conservancy - Northern New York | Pulaski | New York |
| The Nature Conservancy - Rhode Island | Providence | Rhode Island |
| The Nature Conservancy - San Diego | San Diego | California |
| The Nature Conservancy - Texas | Killeen | Texas |
| The Nature Conservancy - Virginia | Charlottesville | Virginia |
| The Nature Conservancy - Wisconsin | Madison | Wisconsin |
| The New York Botanical Garden | Bronx | New York |
| The Pacific Forest Trust | San Francisco | California |
| The Petroleum Institute | Abu Dhabi | International |
| The Pew Charitable Trusts | Washington | District of Columbia |
| The Seattle Public Library | Seattle | Washington |
| The Trustees of Reservations | Leominster | MA |
| The Vitamin Shoppe | North Bergen | New Jersey |
| The Wilderness Society | Washington | District of Columbia |
| The Wildlands Conservancy | Maricopa | California |
| The Wildlands Conservancy | Oak Glen | California |
| The Wildlife Society | Bethesda | Maryland |
| The William and Flora Hewlett Foundation | Menlo Park | California |
| Theodore Roosevelt Conservation Partnership | Washington | District of Columbia |
| Thomas Rose Advertising, Inc. | Marlton | New Jersey |
| Tigercomm | Arlington | Virginia |
| Tillamook Estuaries Partnership | Garibaldi | Oregon |
| Time Global Management | phoenix | Arizona |
| TMP Worldwide | New Albany | Indiana |
| TMP Worldwide | Atlanta | Georgia |
| Topaz Power Group, LP | Austin | Texas |
| Total Reclaim, Inc | Seattle | Washington |
| TRC Raviv Associates | Millburn | New Jersey |
| Tree of Life Rejuvenation Center | Patagonia | Arizona |
| Tree of Life Rejuvenation Center | Patagonia | Arizona |
| TreePeople | Beverly Hills | California |
| Trees For Tomorrow | Eagle River | Wisconsin |
| Tri-State Generation and Transmission Association, Inc. | Denver | Colorado |
| Triumph Enterprises | Canoga Park | California |
| Triumvirate Environmental | Somerville | Massachusetts |
| Tufts University | Somerville | Massachusetts |
| Tufts University - Boston | New London | Connecticut |
| Tuolumne River Trust | San Francisco | California |
| Two Countries One Forest / Deux pays, Une forêt | Halifax | Nova Scotia |
| TYBRIN Corporation | Ft. Walton Beach | Florida |
