Deputy First Minister Nicola Sturgeon announced that the Scottish Government plans to bring forward legislation which would permit it.
The controversial issue has been backed by politicians from all the main parties north of the border, as well as equality campaigners, but has attracted fierce criticism from some religious organisations.
Ms Sturgeon said: "We are committed to a Scotland that is fair and equal, and that is why we intend to proceed with plans to allow same-sex marriage and religious ceremonies for civil partnerships. We believe this is the right thing to do."
The decision comes after almost 80,000 people responded to a Scottish Government consultation on the issue.
The UK Government has also put forward proposals to bring in same-sex marriage, which it supports, but ministers are waiting until the end of a consultation before making a decision on the matter.