The actress said £100,000 was needed to restore the windows at Moat Brae House in Dumfries, where Barrie "dreamed of the Lost Boys, flying and Neverland".
Lumley is a patron of the Peter Pan Moat Brae Trust, set up in 2009 to save the building. She will officially launch the Windows Appeal at the Wigtown Book Festival today.
Speaking ahead of her visit, she said the money would restore the windows, which were "pivotal" to the Peter Pan story, and help ensure Moat Brae House was wind and watertight.
She said: "We saved this extremely beautiful Georgian townhouse just three days before the bulldozers were going to come and knock it away.
"Now we've got this wonderful trust set up to make it into the first home for Scottish children's literature. It's where JM Barrie leaned on the windows with his two young school chums and looked out and dreamed of the Lost Boys, flying and Neverland."