It means that, for the first time, people can now choose to use a .scot web or email address instead of, or as well as, existing options such as .com or .co.uk.
The domain is one of a number of new “top level” domains that are becoming available this year, such as .wales, .london, .berlin and .NYC.
Deputy First Minister Nicola Sturgeon said: “It is entirely right that Scotland should have its own distinctive and recognisable internet domain, in particular one that will resonate internationally, helping to promote Scottish business and culture throughout the world.
“I am confident that the .scot domain name will prove to be a real asset to the people of Scotland and to the worldwide family of Scots.
“I am looking forward to the Scottish Government being able to make use of this new domain, and to having www.gov.scot up and running before the end of the year, as well as our pioneer domains including www.welcome.scot, which will go live today.”
The Scottish Government is one of more than 50 “pioneers” who have signed up to use the .scot domain immediately after its launch.
Other such bodies include NHS Scotland, Yes Scotland and Better Together.
The new internet domain is said to represent the end of a long journey for not-for-profit company Dot Scot Registry.
Director Gavin McCutcheon said: “This is a fantastic day for Scotland online and gives our nation a chance to stand out, and be seen as the digital pioneer that many know it to be.
“Owning a .scot domain will allow people and organisations a new unique way to express their identity online. It’s a community domain intended for everybody who lives and works in Scotland, and for the 50 million people around the globe who are part of Scotland’s diaspora.”
For the next 60 days only “pioneers” will be allowed to use domain but others are invited to register their interest via http://nic.scot. After 23 September, the domain will be open to all to purchase names.