January
- National Bird Day – 5th
- Australia Day – 26th
February
- World Wetlands Day – 2nd
- The Sustainable Living Festival – 11th to 26th
- Business Clean Up Day – 28th
March
- Schools Clean Up Day – 2nd
- Sea Week – 4th to 10th
- Clean Up Australia Day – 4th
- Ground Water Awareness Week – 11th to 17th
- World Forestry Day – 21st
- Harmony Day – 21st
- World Water Day – 22nd
- Close the Gap – 22nd
- World Meteorological Day – 23rd
- Ride2School Day – 23rd
- Earth Hour – 31st
April
- Australian Heritage Week – 14th to 22nd
- World Heritage Day – 18th
- Earth Day – 22nd
- Anzac Day – 25th
May
- OZ’ Water Week 2011 – 8th to 10th
- World Migratory Bird Day – 14th to 15th
- National Volunteer Week – 14th to 20th
- International Museum Day – 18th
- International Day for Biological Diversity – 22nd
- National Sorry Day – 26th
- National Reconciliation Week – 27th to 3rd June
June
- World Environment Day – 5th
- Global Wind Day – 15th
- World Day to Combat Desertification and Drought – 17th
July
- NAIDOC Week – 1st to 8th
- World Population Day – 11th
- Schools Tree Day – 27th
- National Tree Day – 29th
August
- International Day for World Indigenous People – 9th
- Keep Australia Beautiful Week – 22nd to 28th
September
- National Biodiversity Month – all month
- National Wattle Day – 1st
- National Landcare Week – 5th
- Sustainable House Day – 9th
- National Bilby Day – 9th
- International Day for the Preservation of the Ozone Layer – 16th
- 25th anniversary of the signing of the Montreal Protocol – 16th
- Walk To Work Day – 17th
- World Parks Day – 17th
- World Car-Free Day – 22nd
October
- World Habitat Day – 1st
- World Animal Day – 4th
- National Organic Week – 5th to 14th
- National Water Week – 21st to 27th
- National Ride to Work Day – 17th
- Buy Nothing New Month – 17th
November
- International Day for Preventing the Exploitation of the Environment in War and Armed Conflict – 6th
- National Recycling Week – 12th to 18th
- World Fisheries Day – 21st
December
- International Volunteer Day – 5th
- Coastcare Week – TBA
- International Mountain Day – 11th