Parts of Matthew Perry's legacy are set to be sold at auction -- with some seriously iconic "Friends" memorabilia up for grabs ... all for a good cause.

A stash of keepsakes from the late actor -- including artwork, personal items and show memorabilia -- is heading to the June 5 sale via Heritage Auctions ... with proceeds going to the Matthew Perry Foundation, which focuses on destigmatizing addiction and supporting recovery.

The headline grab? A collection of 26 "Friends" scripts from major episodes -- including "The One With Ross's Tan," "The One Where Joey Speaks French" ... and the two-part finale. Even bigger -- scripts from the pilot and Part One of the finale are signed by Perry and his famous costars.

There's more -- we're talking Perry’s 1995 SAG Award for ensemble performance, his "Friends" photo album titled “The One With the Last Supper” ... plus artwork he owned from Banksy and Mel Bochner.

As we reported ... Perry was found dead in his hot tub at his Pacific Palisades home back in October 2023 -- with his death later determined to be caused by the acute effects of ketamine.