The photograph, found at the Royal Commission on the Ancient and Historical Monuments of Scotland (RCAHMS), is 106 years old and was taken in the Corsee area of Nairn, Inverness-shire.
Before the birth of the internet, the word "selfie" was unheard of, but the shot proves that even in the early 20th century, Scots were taking self-portrait pictures with hand-held cameras.
The image was found in some family holiday snaps from an album owned by a woman called Isabel Asher.
In the centre of the picture is a mirror wedged between two rocks and staring back into it with his camera is a young boy, surrounded by clear skies behind him and branches from nearby trees.
But the RCAHMS have no record of who Isabel Asher was and the identity of the well-dressed boy is a complete mystery.
RCAHMS public engagement manager, Philip Graham, said: "People today would certainly appear to be more interested in selfies than ever before.
"You only have to look at the media controversy over the recent photographs of President Obama, David Cameron and the Danish Prime Minister at Nelson Mandela's funeral - and of course, Oxford Dictionary's word of the year is 'selfie'.
"But what we have shown through our archives is that selfies have existed a long time. This is the earliest selfie we know of in Scotland and it will be fascinating to see if anyone out there can find a selfie to beat this one."