The deal does not mean Gaelic becomes an official EU language
A new agreement means Gaelic can now be used formally in meetings between Scottish government ministers and European Union (EU) officials.
The memorandum of understanding on Scots Gaelic is similar to one signed for Welsh last July.
However, the move does not see it added to the EU's list of "official" languages. English is among the 23.
The Scottish government will also have to pay the costs of any translation of Gaelic into another language.
The agreement also allows for correspondence to EU bodies to be written in Gaelic. Responses will be offered in the language.
The UK's representative to the EU, Sir Kim Darroch, and the Scottish government have signed the deal.
Secretary of State for Scotland Jim Murphy said the move was a strong sign of the UK government's support for Gaelic.
He said: "Allowing Gaelic speakers to communicate with European institutions in their mother tongue is a progressive step forward and one which should be welcomed."
Culture Minister Mike Russell said: "This is a significant step forward for the recognition of Gaelic both at home and abroad and I look forward to addressing the council in Gaelic very soon.
"Seeing Gaelic spoken in such a forum raises the profile of the language as we drive forward our commitment to creating a new generation of Gaelic speakers in Scotland."
According to the 2001 census, 92,400 people - 1.9% of Scotland's population - use or understand Gaelic.
Of these people, 58,652 said they could speak it.
The language is protected in Scottish law under the Gaelic Language (Scotland) Act 2005, which also requires public bodies to make greater use of it.
In August, the Scottish government announced an extra £800,000 for a project promoting Gaelic in schools.
The money took the level of funding for the government's Gaelic Schools Fund to £2.15m this year.
In January, the Scottish government embarked on a drive to become more bilingual, through plans including recruiting more Gaelic speakers and encouraging correspondence in the language.
However, Highland Council's Gaelic committee later criticised ministers over the lack of bilingual road signs, and called for them to be introduced on the A9, A96 and A82.
Transport Minister Stewart Stevenson initially referred to anecdotal evidence of motorists performing u-turns after misreading the signs, before later saying the government was seeking to "fast track" the review.