Party officials added that with 20,139 members, the number of people in the SNP was now more than double the total eight years ago, when it was 9,450. They said almost 4,000 new members had signed up over the course of 2011.
Ms Sturgeon said: "Our 20,000-membership milestone is the icing on the Christmas cake for the SNP."
She added that the party's record membership came after a "momentous year for Scottish politics and for the SNP", with the nationalists securing an historic overall majority at Holyrood in May's election.
She continued: "With 20,000 members all working to make Scotland better, the SNP is now the largest party in Scotland and is increasingly the natural choice of those wanting to build a better Scotland.
"We are winning new members and public support as voters recognise the successes of the SNP in Government and our commitment to make Scotland smarter, fairer and wealthier."
Ms Sturgeon said: "Our 20,000-membership milestone is the icing on the Christmas cake for the SNP."
She added that the party's record membership came after a "momentous year for Scottish politics and for the SNP", with the nationalists securing an historic overall majority at Holyrood in May's election.
She continued: "With 20,000 members all working to make Scotland better, the SNP is now the largest party in Scotland and is increasingly the natural choice of those wanting to build a better Scotland.
"We are winning new members and public support as voters recognise the successes of the SNP in Government and our commitment to make Scotland smarter, fairer and wealthier."