diff --git a/app/src/main/java/eu/kanade/tachiyomi/ui/manga/MangaDetailsController.kt b/app/src/main/java/eu/kanade/tachiyomi/ui/manga/MangaDetailsController.kt
index 041da48e12..5424134bc0 100644
--- a/app/src/main/java/eu/kanade/tachiyomi/ui/manga/MangaDetailsController.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/ui/manga/MangaDetailsController.kt
@@ -816,7 +816,12 @@ class MangaDetailsController :
                     }.negativeButton(android.R.string.cancel).show()
             }
             R.id.remove_all, R.id.remove_read, R.id.remove_non_bookmarked -> massDeleteChapters(item.itemId)
-            R.id.action_mark_all_as_unread -> markAsUnread(presenter.chapters)
+            R.id.action_mark_all_as_unread -> {
+                MaterialDialog(view!!.context).message(R.string.mark_all_chapters_as_unread)
+                    .positiveButton(R.string.mark_as_unread) {
+                        markAsUnread(presenter.chapters)
+                    }.negativeButton(android.R.string.cancel).show()
+            }
             R.id.download_next, R.id.download_next_5, R.id.download_custom, R.id.download_unread, R.id.download_all -> downloadChapters(
                 item.itemId
             )
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 001bdee31d..6f61a8f116 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -399,6 +399,7 @@
     <string name="source_not_installed_">Source not installed: %1$s</string>
     <string name="no_description">No description</string>
     <string name="mark_all_chapters_as_read">Mark all chapters as read?</string>
+    <string name="mark_all_chapters_as_unread">Mark all chapters as unread?</string>
     <string name="remove_from_library">Remove from library</string>
     <string name="select_starting_chapter">Select starting chapter</string>
     <string name="select_ending_chapter">Select ending chapter</string>