- Air Alliance Houston
- American Institute of Chemical Engineers — South Texas Section
- American Society of Heating, Refrigerating and Air Conditioning Engineers
- American Youthworks
- Armand Bayou Nature Center
- Artist Boat
- Bayou City Waterkeeper
- Bayou Land Conservancy
- Bayou Preservation Association
- Baytown Environmental Education
- Big Thicket Association
- BikeHouston, Inc.
- Blackwood Land Institute
- Blueprint Houston
- Brays Bayou Association
- Buffalo Bayou Partnership
- Center for Houston’s Future
- Central City Co-Op
- The Children’s Museum of Houston’s EcoStation
- Christmas Bay Foundation
- Coalition for Environment Equity and Resilience
- Citizens’ Climate Lobby
- City of Houston Green Building Resource Center
- Cypress Creek Flood Control Coalition
- Discovery Green Conservancy
- EarthShare of Texas
- EcoRise
- Emerson Unitarian Universalist Church
- Energy Corridor District
- Environment Texas
- Environmental Institute of Houston
- Exploration Green Conservancy
- First Unitarian Universalist Church of Houston
- Flower Garden Banks National Marine Sanctuary
- Friends of Don Greene
- Friends of Mandell Park
- Friends of Woodland Park
- Galveston Bay Foundation
- Galveston Island Nature Tourism Council
- Greens Bayou Coalition
- Galveston Ornithological Society
- Gulf Coast Bird Observatory
- Hermann Park Conservancy
- Houston Advanced Research Center
- Houston Arboretum & Nature Center
- Houston Audubon
- Houston BCycle
- Houston Canoe Club
- Houston Community ToolBank
- Houston Electric Auto Association
- Houston Land and Water Sustainability Forum
- Houston Parks and Recreation Department
- Houston Parks Board
- Houston Peace and Justice Center
- Houston Renewable Energy Group (HREG)
- Houston Tomorrow
- Houston Wilderness
- Houston-Galveston Area Council
- Jesse H. Jones Park & Nature Center
- Katy Prairie Conservancy
- Keep Houston Beautiful
- Keep Kingwood Green
- LINK Houston
- Lower Brazos River Watch
- McMacCX
- Mercer Arboretum & Botanic Gardens
- Native Plant Society of Texas Houston Chapter
- Native Prairies Association of Texas
- Nature Discovery Center
- Outdoor Nature Club
- Public Citizen Texas
- Recipe for Success
- Rice Environmental Analysis Program
- Save Buffalo Bayou
- Sierra Club Houston Regional Group
- SPARK School Park Program
- Student Conservation Association
- Texans for Clean Water
- Texas Association of Environmental Professionals
- Texas Campaign for the Environment
- Texas Community Watershed Partners
- Texas Wildlife Rehabilitation Coalition
- Urban Harvest
- U.S. Green Building Council – Greater Houston Area Chapter
- White Oak Bayou Association
- The Woodlands G.R.E.E.N.
- The Woods Project
Citizens' Environmental Coalition
Connecting Our Environmental Community since 1971
