Backing for the change amongst believers was only 32% in 2002.
The Scottish Social Attitudes revealed that Catholics gave the most support, with 60% saying they were in favour of same sex unions. 59% of people who said they were members of the Church of Scotland backed the change whilst 58% of other Christians were in favour.
The survey has been released as the first Scottish couple changes their civil partnership into a marriage after a change in the law.
Two people of the same sex, who are not already in a civil partnership, will be allowed to get married from December 31.
In England and Wales gay marriage has been legal since October.
Christians leaders were the amongst the most vocal in the campaign against gay married but this survey would appear to suggest some believers disagree with that view.
Although the figure is 60% for Christians over all it falls to 33% for people who go to church every week.
The only group of Scots who still oppose gay marriage is over sixty-fives who go to church regularly.
Rachel Ormston, Co-Director of Social Attitudes at ScotCen Social Research said: "Attitudes within some groups that have been typically more likely to disagree with gay marriage have liberalised considerably over the last four years, and looking at the longer term trends it seems likely that they will continue to do so."