diff --git a/Mac/MainWindow/MainWindowController.swift b/Mac/MainWindow/MainWindowController.swift
index dd243a2fb..122f6dad8 100644
--- a/Mac/MainWindow/MainWindowController.swift
+++ b/Mac/MainWindow/MainWindowController.swift
@@ -402,7 +402,11 @@ class MainWindowController : NSWindowController, NSUserInterfaceValidations {
 			sidebarViewController?.focus()
 		}
 	}
-
+	
+	@IBAction func markOlderArticlesAsRead(_ sender: Any?) {
+		currentTimelineViewController?.markOlderArticlesRead()
+	}
+	
 	@IBAction func markAboveArticlesAsRead(_ sender: Any?) {
 		currentTimelineViewController?.markAboveArticlesRead()
 	}
diff --git a/Mac/MainWindow/Timeline/TimelineViewController.swift b/Mac/MainWindow/Timeline/TimelineViewController.swift
index 2377adc4e..aa6c99766 100644
--- a/Mac/MainWindow/Timeline/TimelineViewController.swift
+++ b/Mac/MainWindow/Timeline/TimelineViewController.swift
@@ -460,6 +460,10 @@ final class TimelineViewController: NSViewController, UndoableCommandRunner, Unr
 		return .canDoNothing
 	}
 
+	func markOlderArticlesRead() {
+		markOlderArticlesRead(selectedArticles)
+	}
+
 	func markAboveArticlesRead() {
 		markAboveArticlesRead(selectedArticles)
 	}
@@ -478,6 +482,33 @@ final class TimelineViewController: NSViewController, UndoableCommandRunner, Unr
 		return articles.articlesBelow(article: last).canMarkAllAsRead()
 	}
 
+	func markOlderArticlesRead(_ selectedArticles: [Article]) {
+		// Mark articles older than the selectedArticles(s) as read.
+
+		var cutoffDate: Date? = nil
+		for article in selectedArticles {
+			if cutoffDate == nil {
+				cutoffDate = article.logicalDatePublished
+			}
+			else if cutoffDate! > article.logicalDatePublished {
+				cutoffDate = article.logicalDatePublished
+			}
+		}
+		if cutoffDate == nil {
+			return
+		}
+
+		let articlesToMark = articles.filter { $0.logicalDatePublished < cutoffDate! }
+		if articlesToMark.isEmpty {
+			return
+		}
+
+		guard let undoManager = undoManager, let markReadCommand = MarkStatusCommand(initialArticles: articlesToMark, markingRead: true, undoManager: undoManager) else {
+			return
+		}
+		runCommand(markReadCommand)
+	}
+
 	func markAboveArticlesRead(_ selectedArticles: [Article]) {
 		guard let first = selectedArticles.first else { return }
 		let articlesToMark = articles.articlesAbove(article: first)