diff --git a/packages/flutter/lib/src/cupertino/dialog.dart b/packages/flutter/lib/src/cupertino/dialog.dart
index 1d71ebeaab..c2deec75e8 100644
--- a/packages/flutter/lib/src/cupertino/dialog.dart
+++ b/packages/flutter/lib/src/cupertino/dialog.dart
@@ -372,7 +372,7 @@ class _CupertinoAlertDialogState extends State<CupertinoAlertDialog> {
 
   Widget _buildBody(BuildContext context) {
     final Color backgroundColor = CupertinoDynamicColor.resolve(_kDialogColor, context);
-    const Color dividerColor = CupertinoColors.separator;
+    final Color dividerColor = CupertinoDynamicColor.resolve(CupertinoColors.separator, context);
     // Remove view padding here because the `Scrollbar` widget uses the view
     // padding as padding, which is unwanted.
     // https://github.com/flutter/flutter/issues/150544
@@ -407,7 +407,14 @@ class _CupertinoAlertDialogState extends State<CupertinoAlertDialog> {
             top: contentSection,
             bottom: Column(
               children: <Widget>[
-                _Divider(dividerColor: dividerColor, hiddenColor: backgroundColor, hidden: false),
+                SizedBox(
+                  width: double.infinity,
+                  child: _Divider(
+                    dividerColor: dividerColor,
+                    hiddenColor: backgroundColor,
+                    hidden: false,
+                  ),
+                ),
                 Flexible(child: scrolledActionsSection),
               ],
             ),
diff --git a/packages/flutter/test/cupertino/dialog_test.dart b/packages/flutter/test/cupertino/dialog_test.dart
index 3046d85a44..96bbcc16e9 100644
--- a/packages/flutter/test/cupertino/dialog_test.dart
+++ b/packages/flutter/test/cupertino/dialog_test.dart
@@ -1988,6 +1988,50 @@ void main() {
       kIsWeb ? SystemMouseCursors.click : SystemMouseCursors.basic,
     );
   });
+
+  testWidgets('CupertinoAlertDialog divider spans full width and applies color', (
+    WidgetTester tester,
+  ) async {
+    const double kCupertinoDialogWidth = 270.0;
+    const double kDividerThickness = 0.3;
+    const Size expectedSize = Size(kCupertinoDialogWidth, kDividerThickness);
+
+    await tester.pumpWidget(
+      CupertinoApp(
+        home: MediaQuery(
+          data: const MediaQueryData(platformBrightness: Brightness.dark),
+          child: CupertinoAlertDialog(
+            title: const Text('The Title'),
+            content: const Text('Content'),
+            actions: <Widget>[
+              CupertinoDialogAction(
+                isDefaultAction: true,
+                onPressed: () {},
+                child: const Text('Cancel'),
+              ),
+              const CupertinoDialogAction(child: Text('OK')),
+            ],
+          ),
+        ),
+      ),
+    );
+
+    final Finder decoratedBoxFinder = find.byType(DecoratedBox);
+
+    expect(decoratedBoxFinder, findsAny, reason: 'There should exist at least one DecoratedBox');
+
+    final Iterable<Element> elements = decoratedBoxFinder.evaluate().where((
+      Element decoratedBoxElement,
+    ) {
+      final DecoratedBox decoratedBox = decoratedBoxElement.widget as DecoratedBox;
+      return (decoratedBox.decoration is BoxDecoration?) &&
+          (decoratedBox.decoration as BoxDecoration?)?.color ==
+              CupertinoDynamicColor.resolve(CupertinoColors.separator, decoratedBoxElement) &&
+          tester.getSize(find.byWidget(decoratedBox)) == expectedSize;
+    });
+
+    expect(elements.length, 1, reason: 'No DecoratedBox matches the specified criteria.');
+  });
 }
 
 RenderBox findActionButtonRenderBoxByTitle(WidgetTester tester, String title) {