This March 26 at 8:30 p.m. millions of people throughout the country will shut off their lights.
According to Earth Hour organizers, this year's event, themed Beyond the Hour, will mark the start of a new phase for the voluntary blackout movement.
This year, they're sounding a global call to individuals, businesses and governments to add more to the annual switch-off by joining an international social network geared toward ecological activity.
Last year lights went out in 128 countries and 4,500 cities worldwide.
Vietnam joined Earth Hour in 2009 and 2010 and millions of individuals, organizations, and businesses participated in the voluntary blackout.
During Earth Hour 2009, Vietnam saved 140,000kWh of electric power mainly in its two major cities.
The following year, the event drew the participation from over 20 cities.
Participants in this year's Earth Hour will switch off their lights and join in celebrations that have been organized all over the world.
Following the actual hour, participants are encouraged to visit the event's website (earthhour.org) and share stories about environmentally conscious activities taking place in their hometown.
The site's content will be shared on its unique online platform, which is translated into 11 languages and integrates with most major social networks, including Facebook, Twitter and Myspace.
So far, over 1,000 local projects and programs have been shared on the dynamic online platform.
Earth Hour started in 2007 in Sydney, Australia when 2.2 million homes and businesses turned their lights off for one hour to make their stand against climate change.
Since then, it has spread all over the globe.