Almost 55,000 people have joined the party following the No vote in the referendum on Scottish independence on September 18.
The SNP described the upsurge in its membership as the “incredible legacy of democratic engagement from the referendum”.
SNP business convener Derek Mackay MSP said: “With this extraordinary surge in membership it’s clear that it is the SNP which people trust to stand up for Scotland’s best interests - and to hold the Westminster establishment to account on their ‘vow’ of substantial new powers.
“The referendum unleashed a new spirit of democratic engagement and participation amongst the people of Scotland - and these people simply won’t accept the same old politics as usual from Westminster.
“The No campaign parties now simply must deliver the real powers we need to make Scotland a fairer, more prosperous country for everyone who lives here. Failure to do so would be completely unacceptable.”