The conservation charity wants to increase its members from a current total of about 375,000 to 490,000, and to up the amount it receives in annual donations to over £10 million.
In its corporate strategy for the period 2018 to 2023, the trust also set the target of increasing visitor numbers to its sites to more than five million a year.
Key amongst its plans will be the construction of a “box” around Charles Rennie Mackintosh’s The Hill House in Helensburgh, in a bid to protect the architecturally renowned property.
The charity is also looking at how it can enhance visitor experience at its properties, as well as preserving them for future generations.
Chief executive Simon Skinner said: “This strategy outlines everything that the National Trust for Scotland stands for - protecting our heritage, sharing unique experiences with people and promoting Scotland, all through the collective endeavour of our supporters and staff.
“To do that, we need to create an efficient and sustainable business which delivers our conservation ambitions.”
He added: “Our charity is unique in Scotland in that its remit is to protect the full spectrum of cultural, built and natural heritage. Our independent charitable status also gives us the freedom to take a long-term view about what is best for heritage, to make our voice heard when it is needed and to take radical action, just as we are doing at The Hill House.
“This plan for the next five years sets out how we can make the Trust fit for the future, through investment in every aspect of our organisation - our people, our places, and delivering the technology that both of them need in an ever-changing world.
“We have a range of bold projects under way the length and breadth of Scotland from The Hill House in Helensburgh and Brodick Castle on Arran, all the way up to our ongoing investment in Inverewe Garden. This strategy gives us a renewed focus on the future and underlines our commitment to the totality of Scotland’s heritage, landscapes, and legacy and what it can do for our communities.”