The castle will join landmarks such as the Empire State Building, Tokyo’s Skytree Tower and the Leaning Tower of Pisa as part of a global initiative to turn the World UN Blue.
Culture, Europe and External Affairs Secretary, Fiona Hyslop, said: “Over the last 70 years the United Nations has protected and improved the lives of so many the world over. Tonight, we want to congratulate the UN on its many achievements and help to promote its message of peace, development and human rights by lighting Edinburgh Castle blue.
“While we celebrate the UN’s 70th anniversary, we know that more work is required by all of us to fulfil the promise of a life in peace and dignity for all that the UN stands for. Scotland shares the UN’s value and goals and is committed to promoting them.
“Many Scottish civil society organisations and individuals work hard to help the UN achieve its aims, often as unpaid volunteers. We want to thank them for this engagement and encourage more people to join their efforts.”