diff --git a/Meta/Lagom/Contrib/MacPDF/CMakeLists.txt b/Meta/Lagom/Contrib/MacPDF/CMakeLists.txt
index 8b3ea1bab4..b1cdbe5803 100644
--- a/Meta/Lagom/Contrib/MacPDF/CMakeLists.txt
+++ b/Meta/Lagom/Contrib/MacPDF/CMakeLists.txt
@@ -17,6 +17,7 @@ add_executable(MacPDF MACOSX_BUNDLE
     main.mm
     AppDelegate.mm
     MacPDFDocument.mm
+    MacPDFOutlineViewDataSource.mm
     MacPDFView.mm
     MacPDFWindowController.mm
 )
diff --git a/Meta/Lagom/Contrib/MacPDF/MacPDFOutlineViewDataSource.h b/Meta/Lagom/Contrib/MacPDF/MacPDFOutlineViewDataSource.h
new file mode 100644
index 0000000000..a91b4cedb2
--- /dev/null
+++ b/Meta/Lagom/Contrib/MacPDF/MacPDFOutlineViewDataSource.h
@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2023, Nico Weber <thakis@chromium.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include "CocoaWrapper.h"
+
+#include <LibPDF/Document.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+// Objective-C wrapper of PDF::OutlineItem, to launder it through the NSOutlineViewDataSource protocol.
+@interface OutlineItemWrapper : NSObject
+
+- (Optional<u32>)page;
+
+@end
+
+@interface MacPDFOutlineViewDataSource : NSObject <NSOutlineViewDataSource>
+
+- (instancetype)initWithOutline:(RefPtr<PDF::OutlineDict>)outline;
+
+@end
+
+NS_ASSUME_NONNULL_END
diff --git a/Meta/Lagom/Contrib/MacPDF/MacPDFOutlineViewDataSource.mm b/Meta/Lagom/Contrib/MacPDF/MacPDFOutlineViewDataSource.mm
new file mode 100644
index 0000000000..6dcf6b6e0f
--- /dev/null
+++ b/Meta/Lagom/Contrib/MacPDF/MacPDFOutlineViewDataSource.mm
@@ -0,0 +1,89 @@
+/*
+ * Copyright (c) 2023, Nico Weber <thakis@chromium.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#import "MacPDFOutlineViewDataSource.h"
+
+@interface OutlineItemWrapper ()
+{
+    RefPtr<PDF::OutlineItem> _item;
+}
+@end
+
+@implementation OutlineItemWrapper
+- (instancetype)initWithItem:(NonnullRefPtr<PDF::OutlineItem>)item
+{
+    if (self = [super init]; !self)
+        return nil;
+    _item = move(item);
+    return self;
+}
+
+- (Optional<u32>)page
+{
+    return _item->dest.page.map([](u32 page_index) { return page_index + 1; });
+}
+
+- (OutlineItemWrapper*)child:(NSInteger)index
+{
+    return [[OutlineItemWrapper alloc] initWithItem:_item->children[index]];
+}
+
+- (NSInteger)numberOfChildren
+{
+    return _item->children.size();
+}
+
+- (NSString*)objectValue
+{
+    return [NSString stringWithFormat:@"%s", _item->title.characters()]; // FIXME: encoding?
+}
+@end
+
+@interface MacPDFOutlineViewDataSource ()
+{
+    RefPtr<PDF::OutlineDict> _outline;
+}
+@end
+
+@implementation MacPDFOutlineViewDataSource
+
+- (instancetype)initWithOutline:(RefPtr<PDF::OutlineDict>)outline
+{
+    if (self = [super init]; !self)
+        return nil;
+    _outline = move(outline);
+    return self;
+}
+
+#pragma mark - NSOutlineViewDataSource
+
+- (id)outlineView:(NSOutlineView*)outlineView child:(NSInteger)index ofItem:(nullable id)item
+{
+    if (item)
+        return [(OutlineItemWrapper*)item child:index];
+
+    return [[OutlineItemWrapper alloc] initWithItem:_outline->children[index]];
+}
+
+- (BOOL)outlineView:(NSOutlineView*)outlineView isItemExpandable:(id)item
+{
+    return [self outlineView:outlineView numberOfChildrenOfItem:item] > 0;
+}
+
+- (NSInteger)outlineView:(NSOutlineView*)outlineView numberOfChildrenOfItem:(nullable id)item
+{
+    if (item)
+        return [(OutlineItemWrapper*)item numberOfChildren];
+
+    return _outline ? _outline->children.size() : 0;
+}
+
+- (id)outlineView:(NSOutlineView*)outlineView objectValueForTableColumn:(nullable NSTableColumn*)tableColumn byItem:(nullable id)item
+{
+    return [(OutlineItemWrapper*)item objectValue];
+}
+
+@end