| "The Old Castle's Secret" | |
|---|---|
 Original cover by Carl Barks | |
| Story code | W OS 189-02 |
| Story | Carl Barks |
| Ink | Carl Barks |
| Date | December 3, 1947 |
| Hero | Donald Duck |
| Pages | 32 |
| Layout | 4 rows per page |
| Appearances | Donald Duck Huey, Dewey, and Louie Scrooge McDuck |
| First publication | Four Color Comics #189 June 1948 |
"The Old Castle's Secret" is a 32-page Disney comics adventure/mystery/horror story written, drawn, and lettered by Carl Barks. It was first published by Dell Publishing in Four Color #189 (June 1948). Characters include Scrooge McDuck, Donald Duck, and his three nephews. The story is about a treasure hunt led by Uncle Scrooge through an old castle in Scotland.
This is the first of Uncle Scrooge's comic book treasure hunts, and the cover is Barks' first. The story has been reprinted many times.