diff --git a/Tethering/src/com/android/networkstack/tethering/Tethering.java b/Tethering/src/com/android/networkstack/tethering/Tethering.java
index 5191bb7..0d1b22e 100644
--- a/Tethering/src/com/android/networkstack/tethering/Tethering.java
+++ b/Tethering/src/com/android/networkstack/tethering/Tethering.java
@@ -97,6 +97,7 @@
 import android.net.TetheringInterface;
 import android.net.TetheringManager.TetheringRequest;
 import android.net.TetheringRequestParcel;
+import android.net.Uri;
 import android.net.ip.IpServer;
 import android.net.wifi.WifiClient;
 import android.net.wifi.WifiManager;
@@ -343,9 +344,8 @@
                     mEntitlementMgr.reevaluateSimCardProvisioning(mConfig);
                 });
 
-        mSettingsObserver = new SettingsObserver(mHandler);
-        mContext.getContentResolver().registerContentObserver(
-                Settings.Global.getUriFor(TETHER_FORCE_USB_FUNCTIONS), false, mSettingsObserver);
+        mSettingsObserver = new SettingsObserver(mContext, mHandler);
+        mSettingsObserver.startObserve();
 
         mStateReceiver = new StateReceiver();
 
@@ -397,18 +397,42 @@
     }
 
     private class SettingsObserver extends ContentObserver {
-        SettingsObserver(Handler handler) {
+        private final Uri mForceUsbFunctions;
+        private final Uri mTetherSupported;
+        private final Context mContext;
+
+        SettingsObserver(Context ctx, Handler handler) {
             super(handler);
+            mContext = ctx;
+            mForceUsbFunctions = Settings.Global.getUriFor(TETHER_FORCE_USB_FUNCTIONS);
+            mTetherSupported = Settings.Global.getUriFor(Settings.Global.TETHER_SUPPORTED);
+        }
+
+        public void startObserve() {
+            mContext.getContentResolver().registerContentObserver(mForceUsbFunctions, false, this);
+            mContext.getContentResolver().registerContentObserver(mTetherSupported, false, this);
         }
 
         @Override
         public void onChange(boolean selfChange) {
-            mLog.i("OBSERVED Settings change");
-            final boolean isUsingNcm = mConfig.isUsingNcm();
-            updateConfiguration();
-            if (isUsingNcm != mConfig.isUsingNcm()) {
-                stopTetheringInternal(TETHERING_USB);
-                stopTetheringInternal(TETHERING_NCM);
+            Log.wtf(TAG, "Should never be reached.");
+        }
+
+        @Override
+        public void onChange(boolean selfChange, Uri uri) {
+            if (mForceUsbFunctions.equals(uri)) {
+                mLog.i("OBSERVED TETHER_FORCE_USB_FUNCTIONS settings change");
+                final boolean isUsingNcm = mConfig.isUsingNcm();
+                updateConfiguration();
+                if (isUsingNcm != mConfig.isUsingNcm()) {
+                    stopTetheringInternal(TETHERING_USB);
+                    stopTetheringInternal(TETHERING_NCM);
+                }
+            } else if (mTetherSupported.equals(uri)) {
+                mLog.i("OBSERVED TETHER_SUPPORTED settings change");
+                updateSupportedDownstreams(mConfig);
+            } else {
+                mLog.e("Unexpected settings change: " + uri);
             }
         }
     }
@@ -1322,7 +1346,9 @@
         }
 
         private void handleUserRestrictionAction() {
-            mTetheringRestriction.onUserRestrictionsChanged();
+            if (mTetheringRestriction.onUserRestrictionsChanged()) {
+                updateSupportedDownstreams(mConfig);
+            }
         }
 
         private void handleDataSaverChanged() {
@@ -1350,6 +1376,8 @@
         return getTetheredIfaces().length > 0;
     }
 
+    // TODO: Refine TetheringTest then remove UserRestrictionActionListener class and handle
+    // onUserRestrictionsChanged inside Tethering#handleUserRestrictionAction directly.
     @VisibleForTesting
     protected static class UserRestrictionActionListener {
         private final UserManager mUserMgr;
@@ -1365,7 +1393,8 @@
             mDisallowTethering = false;
         }
 
-        public void onUserRestrictionsChanged() {
+        // return whether tethering disallowed is changed.
+        public boolean onUserRestrictionsChanged() {
             // getUserRestrictions gets restriction for this process' user, which is the primary
             // user. This is fine because DISALLOW_CONFIG_TETHERING can only be set on the primary
             // user. See UserManager.DISALLOW_CONFIG_TETHERING.
@@ -1376,15 +1405,13 @@
             mDisallowTethering = newlyDisallowed;
 
             final boolean tetheringDisallowedChanged = (newlyDisallowed != prevDisallowed);
-            if (!tetheringDisallowedChanged) {
-                return;
-            }
+            if (!tetheringDisallowedChanged) return false;
 
             if (!newlyDisallowed) {
                 // Clear the restricted notification when user is allowed to have tethering
                 // function.
                 mNotificationUpdater.tetheringRestrictionLifted();
-                return;
+                return true;
             }
 
             if (mTethering.isTetheringActive()) {
@@ -1395,6 +1422,8 @@
                 // Untether from all downstreams since tethering is disallowed.
                 mTethering.untetherAll();
             }
+
+            return true;
             // TODO(b/148139325): send tetheringSupported on restriction change
         }
     }
diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringTest.java b/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringTest.java
index 66ad167..a36d67f 100644
--- a/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringTest.java
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/TetheringTest.java
@@ -2899,9 +2899,13 @@
     }
 
     private void forceUsbTetheringUse(final int function) {
-        Settings.Global.putInt(mContentResolver, TETHER_FORCE_USB_FUNCTIONS, function);
+        setSetting(TETHER_FORCE_USB_FUNCTIONS, function);
+    }
+
+    private void setSetting(final String key, final int value) {
+        Settings.Global.putInt(mContentResolver, key, value);
         final ContentObserver observer = mTethering.getSettingsObserverForTest();
-        observer.onChange(false /* selfChange */);
+        observer.onChange(false /* selfChange */, Settings.Global.getUriFor(key));
         mLooper.dispatchAll();
     }
 
@@ -2957,74 +2961,86 @@
                 TETHERING_WIFI_P2P, TETHERING_BLUETOOTH, TETHERING_ETHERNET });
     }
 
+    private void setUserRestricted(boolean restricted) {
+        final Bundle restrictions = new Bundle();
+        restrictions.putBoolean(UserManager.DISALLOW_CONFIG_TETHERING, restricted);
+        when(mUserManager.getUserRestrictions()).thenReturn(restrictions);
+        when(mUserManager.hasUserRestriction(
+                UserManager.DISALLOW_CONFIG_TETHERING)).thenReturn(restricted);
+
+        final Intent intent = new Intent(UserManager.ACTION_USER_RESTRICTIONS_CHANGED);
+        mServiceContext.sendBroadcastAsUser(intent, UserHandle.ALL);
+        mLooper.dispatchAll();
+    }
+
     @Test
     public void testTetheringSupported() throws Exception {
         final ArraySet<Integer> expectedTypes = getAllSupportedTetheringTypes();
         // Check tethering is supported after initialization.
-        setTetheringSupported(true /* supported */);
         TestTetheringEventCallback callback = new TestTetheringEventCallback();
         mTethering.registerTetheringEventCallback(callback);
         mLooper.dispatchAll();
-        updateConfigAndVerifySupported(callback, expectedTypes);
+        verifySupported(callback, expectedTypes);
 
-        // Could disable tethering supported by settings.
-        Settings.Global.putInt(mContentResolver, Settings.Global.TETHER_SUPPORTED, 0);
-        updateConfigAndVerifySupported(callback, new ArraySet<>());
+        // Could change tethering supported by settings.
+        setSetting(Settings.Global.TETHER_SUPPORTED, 0);
+        verifySupported(callback, new ArraySet<>());
+        setSetting(Settings.Global.TETHER_SUPPORTED, 1);
+        verifySupported(callback, expectedTypes);
 
-        // Could disable tethering supported by user restriction.
-        setTetheringSupported(true /* supported */);
-        updateConfigAndVerifySupported(callback, expectedTypes);
-        when(mUserManager.hasUserRestriction(
-                UserManager.DISALLOW_CONFIG_TETHERING)).thenReturn(true);
-        updateConfigAndVerifySupported(callback, new ArraySet<>());
+        // Could change tethering supported by user restriction.
+        setUserRestricted(true /* restricted */);
+        verifySupported(callback, new ArraySet<>());
+        setUserRestricted(false /* restricted */);
+        verifySupported(callback, expectedTypes);
 
-        // Tethering is supported if it has any supported downstream.
-        setTetheringSupported(true /* supported */);
-        updateConfigAndVerifySupported(callback, expectedTypes);
         // Usb tethering is not supported:
         expectedTypes.remove(TETHERING_USB);
         when(mResources.getStringArray(R.array.config_tether_usb_regexs))
                 .thenReturn(new String[0]);
-        updateConfigAndVerifySupported(callback, expectedTypes);
+        sendConfigurationChanged();
+        verifySupported(callback, expectedTypes);
         // Wifi tethering is not supported:
         expectedTypes.remove(TETHERING_WIFI);
         when(mResources.getStringArray(R.array.config_tether_wifi_regexs))
                 .thenReturn(new String[0]);
-        updateConfigAndVerifySupported(callback, expectedTypes);
+        sendConfigurationChanged();
+        verifySupported(callback, expectedTypes);
         // Bluetooth tethering is not supported:
         expectedTypes.remove(TETHERING_BLUETOOTH);
         when(mResources.getStringArray(R.array.config_tether_bluetooth_regexs))
                 .thenReturn(new String[0]);
 
         if (isAtLeastT()) {
-            updateConfigAndVerifySupported(callback, expectedTypes);
+            sendConfigurationChanged();
+            verifySupported(callback, expectedTypes);
 
             // P2p tethering is not supported:
             expectedTypes.remove(TETHERING_WIFI_P2P);
             when(mResources.getStringArray(R.array.config_tether_wifi_p2p_regexs))
                     .thenReturn(new String[0]);
-            updateConfigAndVerifySupported(callback, expectedTypes);
+            sendConfigurationChanged();
+            verifySupported(callback, expectedTypes);
             // Ncm tethering is not supported:
             expectedTypes.remove(TETHERING_NCM);
             when(mResources.getStringArray(R.array.config_tether_ncm_regexs))
                     .thenReturn(new String[0]);
-            updateConfigAndVerifySupported(callback, expectedTypes);
+            sendConfigurationChanged();
+            verifySupported(callback, expectedTypes);
             // Ethernet tethering (last supported type) is not supported:
             expectedTypes.remove(TETHERING_ETHERNET);
             mForceEthernetServiceUnavailable = true;
-            updateConfigAndVerifySupported(callback, new ArraySet<>());
-
+            sendConfigurationChanged();
+            verifySupported(callback, new ArraySet<>());
         } else {
             // If wifi, usb and bluetooth are all not supported, all the types are not supported.
-            expectedTypes.clear();
-            updateConfigAndVerifySupported(callback, expectedTypes);
+            sendConfigurationChanged();
+            verifySupported(callback, new ArraySet<>());
         }
     }
 
-    private void updateConfigAndVerifySupported(final TestTetheringEventCallback callback,
+    private void verifySupported(final TestTetheringEventCallback callback,
             final ArraySet<Integer> expectedTypes) {
-        sendConfigurationChanged();
-
         assertEquals(expectedTypes.size() > 0, mTethering.isTetheringSupported());
         callback.expectSupportedTetheringTypes(expectedTypes);
     }