The house, its research library and traditional farms all secured full accreditation in the Museum Standards Programme.
The only other institution to obtain full accreditation was the National Gallery of Ireland.
According to Muckross House chief executive Pat Dawson, a huge amount of work went into the making of submissions for the award over a three-year period, led by research and education officer Patricia O’Hare.
A total of 24 files covering eight headings were prepared for assessment.
“This accreditation has been aspired to by everyone associated with Muckross House since the house was first opened to the public as a folk museum in 1964,” said Mr Dawson.
“This status now opens up the possibility of bringing very rare artefacts, including some from other countries, to Killarney. It puts Muckross House into the top bracket of museums.”
Chairman of Muckross House trustees Michael Gleeson said it was a notable achievement, particularly in view of the fact that the trustees formed a not-for-profit, voluntary body without access to the level of resources available to national cultural institutions.
The trustees are continuing with botanical research on the monastic island of Innisfallen, in Lough Lein. One of the aims is to ascertain if plants and herbs used by monks on the island, 1,000 years ago, had medicinal qualities.
Innisfallen, which is easily accessible from Ross Castle, contains well preserved monastic ruins and is visited by thousands of tourists annually.
Also being explored is the possibility of establishing a lake history and boating museum in Killarney, which has a long history of boating on the world-famous lakes.
Meanwhile, work is continuing to restore the house, built in 1843, to its Victorian splendour.
The queen’s boudoir, in which Queen Victoria stayed for two nights during her 1861 visit to Killarney, has already been restored, along with several other rooms.
A recent project was the expert treatment and conservation of upholstery on the north and west windows of the dining room by Cliodna Devitt.
In preparation for the royal visit, Henry Arthur Herbert and his wife Mary, then owners of the house, undertook a major redecoration, which included the dining room upholstery. Apart from being removed for minor repair work and partial relining, the upholstery had dressed the dining room windows since that time.
Meanwhile, calls have been made in Killarney for the inclusion of the area in an itinerary for the current Queen of England, should she visit the country in the future.