And this year the yacht received a record score of 96%, the highest mark ever awarded to a visitor attraction in Scotland.
It was rated by national tourism organisation VisitScotland.
VisitScotland's quality assurance scheme, is the official measure of quality for tourism businesses.
Tourism businesses are assessed on the welcome, attitude, knowledge and efficiency of staff, as well as audience level, interpretation, maintenance and cleanliness.
With 308,906 visitors in 2015, the Royal Yacht last week announced 2015 as its best since its opening year in 1999.
Almost five million people from around the world have visited The Queen's former yacht since it opened to visitors in Edinburgh in 1998.
Britannia's chief executive Bob Downie said: "To be the best in Scotland once is a fantastic achievement, but to do this for 10 consecutive years is a phenomenal tribute to our staff who go the extra mile to ensure that all our visitors have a great experience when they visit Britannia.
"The true test of any great organisation is consistency of performance, delivering great value for time and money, year in year out, and there is no doubt that our pioneering approach to providing great customer experiences has underpinned our success."
Malcolm Roughead, VisitScotland's chief executive, said: "I'd like to congratulate Britannia on this fantastic achievement, which demonstrates an outstanding commitment to quality and excellence in every aspect of the business.
"Retaining the accolade of Scotland's best attraction for 10 years running, Britannia is setting the standards for tourism in Scotland, and it is a real testament to the total commitment shown by their staff to consistently deliver a world-leading customer experience."

Cleveland Police have also confirmed a 26-year-old man has been arrested on suspicion of child abduction, following the girl's disappearance on Thursday.
The girl from Teesside was found earlier, after being reported missing at 22:00 BST.
The search for her involved 30 officers.

An altercation broke out between two men inside a fast food outlet about 00:35 BST on Sunday which then continued outside.
Police said the suspect is described being aged in his early 20s, of slim to medium build, with cropped dark hair shaved on both sides.
Police have appealed for information.

Transport for London (TfL) announced a public consultation process to decide how the city's private hire trade should be regulated.
Proposals include improving the driving and English language skills of drivers and stricter insurance requirements.
But Uber said that the proposals would raise prices and add to congestion in London.
"It's meant to be a public consultation but it clearly hasn't got the public's interests at heart," said Gareth Mead, Uber Europe's spokesperson on the Today programme.
An online petition called called Support Uber London has received more than 123,000 signatures, stating that the proposals would lead to a five minute waiting time before a customer can begin their Uber journey.
"There will be a mandatory five minute wait time, even if a car is available just around the corner. You won't even be able to see the nearest cars when you open the app", the petition claimed.
Mr Mead said of the proposed five-minute wait for trip confirmation: "As the night's draw in, it's starting to get colder and darker. I'm not quite sure how that [proposal] benefits anybody."
Earlier this week Garrett Emmerson, a senior executive at TfL, said in a statement: "In recent years the private hire industry has grown exponentially and technology has also developed rapidly. The consultation sets out a number of ways that standards across the industry could be raised.
"No final decisions have been made and we're keen to hear a range of views from the trade and from Londoners too."
The Californian technology company has faced resistance from taxi drivers around the world, who argue that Uber drivers escape regulation.
But Mr Mead said Uber drivers are subject to the same measures which govern the private hire industry, including background checks and licensing requirements.
Responding to criticism that Uber cannot ensure that its drivers are taking rest breaks, Mr Mead said: "One of the advantages of a digital technology company is that you can see, to the minute, what they [drivers] are doing, and we tell them when they need to take a break."
Mr Mead said that since Uber launched in London a year ago, it had gained 1 million users in the capital.
The Royal Yacht Britannia has been judged as Scotland's best visitor attraction every year for the past decade.
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A missing girl believed to have left home to see a man she met online has been found, say police.
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A man in his 30s is in a serious condition in hospital after suffering a head injury during an assault in Belfast city centre.
[NEXT_CONCEPT]
Taxi hiring app Uber said London's transport authority is proposing rules that are "against the public interest".