diff --git a/app/src/common/shared/org/mozilla/vrbrowser/browser/PromptDelegate.java b/app/src/common/shared/org/mozilla/vrbrowser/browser/PromptDelegate.java
index 832984da1..7768e0bd8 100644
--- a/app/src/common/shared/org/mozilla/vrbrowser/browser/PromptDelegate.java
+++ b/app/src/common/shared/org/mozilla/vrbrowser/browser/PromptDelegate.java
@@ -12,6 +12,7 @@
 import org.mozilla.geckoview.AllowOrDeny;
 import org.mozilla.geckoview.GeckoResult;
 import org.mozilla.geckoview.GeckoSession;
+import org.mozilla.geckoview.SlowScriptResponse;
 import org.mozilla.vrbrowser.AppExecutors;
 import org.mozilla.vrbrowser.R;
 import org.mozilla.vrbrowser.VRBrowserApplication;
@@ -37,7 +38,8 @@
 public class PromptDelegate implements
         GeckoSession.PromptDelegate,
         WindowWidget.WindowListener,
-        GeckoSession.NavigationDelegate {
+        GeckoSession.NavigationDelegate,
+        GeckoSession.ContentDelegate {
 
     public interface PopUpDelegate {
         void onPopUpAvailable();
@@ -46,6 +48,7 @@ public interface PopUpDelegate {
 
     private PromptWidget mPrompt;
     private PopUpBlockDialogWidget mPopUpPrompt;
+    private ConfirmPromptWidget mSlowScriptPrompt;
     private Context mContext;
     private WindowWidget mAttachedWindow;
     private List<PopUpSite> mAllowedPopUpSites;
@@ -99,11 +102,13 @@ private Session getSession() {
     private void setUpSession(@NonNull Session aSession) {
         aSession.setPromptDelegate(this);
         aSession.addNavigationListener(this);
+        aSession.addContentListener(this);
     }
 
     private void cleanSession(@NonNull Session aSession) {
         aSession.setPromptDelegate(null);
         aSession.removeNavigationListener(this);
+        aSession.removeContentListener(this);
         mPopUpRequests.remove(aSession.hashCode());
     }
 
@@ -389,6 +394,43 @@ private void showPopUp(int sessionId, @NonNull Pair<String, LinkedList<PopUpRequ
         }
     }
 
+    @Nullable
+    @Override
+    public GeckoResult<SlowScriptResponse> onSlowScript(@NonNull GeckoSession aSession, @NonNull String aScriptFileName) {
+        final GeckoResult<SlowScriptResponse> result = new GeckoResult<>();
+        if (mSlowScriptPrompt == null) {
+            mSlowScriptPrompt = new ConfirmPromptWidget(mContext);
+            mSlowScriptPrompt.getPlacement().parentHandle = mAttachedWindow.getHandle();
+            mSlowScriptPrompt.getPlacement().parentAnchorY = 0.0f;
+            mSlowScriptPrompt.getPlacement().translationY = WidgetPlacement.unitFromMeters(mContext, R.dimen.base_app_dialog_y_distance);
+            mSlowScriptPrompt.setTitle(mContext.getResources().getString(R.string.slow_script_dialog_title));
+            mSlowScriptPrompt.setMessage(mContext.getResources().getString(R.string.slow_script_dialog_description, aScriptFileName));
+            mSlowScriptPrompt.setButtons(new String[]{
+                    mContext.getResources().getString(R.string.slow_script_dialog_action_wait),
+                    mContext.getResources().getString(R.string.slow_script_dialog_action_stop)
+            });
+            mSlowScriptPrompt.setPromptDelegate(new ConfirmPromptWidget.ConfirmPromptDelegate() {
+                @Override
+                public void confirm(int index) {
+                    result.complete(index == 0 ? SlowScriptResponse.CONTINUE : SlowScriptResponse.STOP);
+                }
+                @Override
+                public void dismiss() {
+                    result.complete(SlowScriptResponse.CONTINUE);
+                }
+            });
+            mSlowScriptPrompt.show(UIWidget.REQUEST_FOCUS);
+        }
+
+        return result.then(value -> {
+            if (mSlowScriptPrompt != null && !mSlowScriptPrompt.isReleased()) {
+                mSlowScriptPrompt.releaseWidget();
+            }
+            mSlowScriptPrompt = null;
+            return GeckoResult.fromValue(value);
+        });
+    }
+
     // WindowWidget.WindowListener
 
     @Override
diff --git a/app/src/common/shared/org/mozilla/vrbrowser/browser/engine/Session.java b/app/src/common/shared/org/mozilla/vrbrowser/browser/engine/Session.java
index 5bf88e528..725212c20 100644
--- a/app/src/common/shared/org/mozilla/vrbrowser/browser/engine/Session.java
+++ b/app/src/common/shared/org/mozilla/vrbrowser/browser/engine/Session.java
@@ -30,6 +30,7 @@
 import org.mozilla.geckoview.GeckoSession;
 import org.mozilla.geckoview.GeckoSessionSettings;
 import org.mozilla.geckoview.MediaElement;
+import org.mozilla.geckoview.SlowScriptResponse;
 import org.mozilla.geckoview.WebRequestError;
 import org.mozilla.vrbrowser.R;
 import org.mozilla.vrbrowser.browser.Media;
@@ -1029,6 +1030,20 @@ public void onFirstContentfulPaint(@NonNull GeckoSession aSession) {
         }
     }
 
+    @Nullable
+    @Override
+    public GeckoResult<SlowScriptResponse> onSlowScript(@NonNull GeckoSession aSession, @NonNull String aScriptFileName) {
+        if (mState.mSession == aSession) {
+            for (GeckoSession.ContentDelegate listener : mContentListeners) {
+                GeckoResult<SlowScriptResponse> result = listener.onSlowScript(aSession, aScriptFileName);
+                if (result != null) {
+                    return result;
+                }
+            }
+        }
+        return null;
+    }
+
     // TextInput Delegate
 
     @Override
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index e690a70ee..ac7526bc5 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -1304,4 +1304,20 @@ the Select` button. When clicked it closes all the previously selected tabs -->
     <!-- This string is displayed a button of the what's new dialog that is displayed if the user has updated
          or updated the app and hasn't signed it yet. If clicked the dialog is dismissed. -->
     <string name="whats_new_button_start_browsing">Start Browsing</string>
+
+
+    <!-- This string is displayed in the title of the slow script dialog. -->
+    <string name="slow_script_dialog_title">Slow script</string>
+
+    <!-- This string is displayed as a description below the title of slow script dialog.
+        '%1$s' will be replaced the script filename that is causing the slow down. -->
+    <string name="slow_script_dialog_description">A web page is slowing down your browser (%1$s). What would you like to do?</string>
+
+    <!-- This string is displayed as a button below the slow script dialog description message. When clicked
+        it stops the slow script that is causing the web page slow down. -->
+    <string name="slow_script_dialog_action_stop">Stop it</string>
+
+    <!-- This string is displayed as a button below the slow script dialog description message. When clicked
+       it continues to wait for execution of the web page script that caused the slow down. -->
+    <string name="slow_script_dialog_action_wait">Wait</string>
 </resources>