These 37 climate groups and environmental organisations have endorsed and support the Mass Mailout for Climate campaign. Together, they represent and reach 1,356,021 Australians:
| 1 Million Women |
| A Different Approach Community (ADAC) |
| A Grand Stand for Environment (AGSE) |
| ACF Melbourne NxNW |
| Adelaide School Strike 4 Climate |
| Australian Conservation Foundation |
| Australian Forests and Climate Alliance |
| Australian Religious Response to Climate Change (ARRCC) |
| Banyule Climate Action Network |
| Bayside Climate Crisis Action |
| Baw Baw Sustainability Network |
| Capricorn Conservation Council |
| Centre for Climate Safety |
| Clarence Climate Action |
| Climate and Health Alliance (CAHA) |
| Darebin Climate Action Now |
| Environment Victoria |
| Environmentally Concerned Citizens Orange |
| Extinction Rebellion Australia |
| Geelong Sustainability |
| Gloucester Transition Inc |
| Householders Protect Environment |
| Journeys for Climate Justice |
| Lighter Footprints |
| Nature Coast Marine Group |
| Outdoors People for Climate |
| Parramatta Climate Action Network |
| Queenscliff Climate Action Group |
| South East Region Con Alliance |
| Stop Adani Albury Wodonga |
| Sustainable Population Australia |
| Sustainable Population Australia WA Branch |
| Transition Australia |
| Vote Earth Now |
| Warrandyte Climate Action Now |
| Wondonga Albury Towards Climate |
| Yarra Climate Action Now |