The cowboy icon wore the iconic patch as Rooster Cogburn in the classic 1969 Western, and again in 1975 sequel Rooster Cogburn.
He donated the patch to the Southern California Symphony Society in 1975 and wrote a letter to accompany the item, joking, "Now that my eye is better I'm happy to donate it to such a worthy cause... Wear it in good health!"
Wayne famously credited the eyepatch for the Oscar he won for True Grit, joking, "If I'd known, I'd have put the patch on 35 years earlier."
The patch will be auctioned online by Nate Sanders, who called the prop the "ultimate piece for fans of the western movie, a uniquely American genre".
The item will go under the hammer on 29 May (12).