diff --git a/packages/SystemUI/aconfig/accessibility.aconfig b/packages/SystemUI/aconfig/accessibility.aconfig
index 8860452..5251246 100644
--- a/packages/SystemUI/aconfig/accessibility.aconfig
+++ b/packages/SystemUI/aconfig/accessibility.aconfig
@@ -4,6 +4,16 @@
 # NOTE: Keep alphabetized to help limit merge conflicts from multiple simultaneous editors.
 
 flag {
+    name: "add_black_background_for_window_magnifier"
+    namespace: "accessibility"
+    description: "Set the background for SurfaceView in window magnification black."
+    bug: "299981434"
+    metadata {
+      purpose: PURPOSE_BUGFIX
+    }
+}
+
+flag {
     name: "create_windowless_window_magnifier"
     namespace: "accessibility"
     description: "Uses SurfaceControlViewHost to create the magnifier for window magnification."
diff --git a/packages/SystemUI/src/com/android/systemui/accessibility/WindowMagnificationController.java b/packages/SystemUI/src/com/android/systemui/accessibility/WindowMagnificationController.java
index 3828f9f..f0483a5 100644
--- a/packages/SystemUI/src/com/android/systemui/accessibility/WindowMagnificationController.java
+++ b/packages/SystemUI/src/com/android/systemui/accessibility/WindowMagnificationController.java
@@ -112,6 +112,7 @@
             MagnificationConstants.SCALE_MAX_VALUE);
     private static final float A11Y_CHANGE_SCALE_DIFFERENCE = 1.0f;
     private static final float ANIMATION_BOUNCE_EFFECT_SCALE = 1.05f;
+    private static final float[] COLOR_BLACK_ARRAY = {0f, 0f, 0f};
     private final SparseArray<Float> mMagnificationSizeScaleOptions = new SparseArray<>();
 
     private final Context mContext;
@@ -1019,6 +1020,11 @@
         if (!mMirrorSurface.isValid()) {
             return;
         }
+        // Set the surface of the SurfaceView to black to avoid users seeing the contents below the
+        // magnifier when the mirrored surface has an alpha less than 1.
+        if (Flags.addBlackBackgroundForWindowMagnifier()) {
+            mTransaction.setColor(mMirrorSurfaceView.getSurfaceControl(), COLOR_BLACK_ARRAY);
+        }
         mTransaction.show(mMirrorSurface)
                 .reparent(mMirrorSurface, mMirrorSurfaceView.getSurfaceControl());
         modifyWindowMagnification(false);