diff --git a/onionshare_gui/main_window.py b/onionshare_gui/main_window.py
index c2db80ec..a518ab33 100644
--- a/onionshare_gui/main_window.py
+++ b/onionshare_gui/main_window.py
@@ -268,8 +268,32 @@ class MainWindow(QtWidgets.QMainWindow):
 
     def closeEvent(self, e):
         self.common.log("MainWindow", "closeEvent")
+
+        if self.tabs.are_tabs_active():
+            # Open the warning dialog
+            dialog = QtWidgets.QMessageBox()
+            dialog.setWindowTitle(strings._("gui_quit_warning_title"))
+            dialog.setText(strings._("gui_quit_warning_description"))
+            dialog.setIcon(QtWidgets.QMessageBox.Critical)
+            dialog.addButton(
+                strings._("gui_quit_warning_quit"), QtWidgets.QMessageBox.YesRole
+            )
+            cancel_button = dialog.addButton(
+                strings._("gui_quit_warning_cancel"), QtWidgets.QMessageBox.NoRole
+            )
+            dialog.setDefaultButton(cancel_button)
+            reply = dialog.exec_()
+
+            # Close
+            if reply == 0:
+                self.system_tray.hide()
+                e.accept()
+            # Cancel
+            else:
+                e.ignore()
+            return
+
         self.system_tray.hide()
-        # TODO: Run the tab's close_event
         e.accept()
 
     def cleanup(self):
diff --git a/onionshare_gui/tab/tab.py b/onionshare_gui/tab/tab.py
index 316012c6..4b4127fd 100644
--- a/onionshare_gui/tab/tab.py
+++ b/onionshare_gui/tab/tab.py
@@ -500,6 +500,14 @@ class Tab(QtWidgets.QWidget):
         """
         self.status_bar.clearMessage()
 
+    def get_mode(self):
+        if self.mode == self.common.gui.MODE_SHARE:
+            return self.share_mode
+        elif self.mode == self.common.gui.MODE_RECEIVE:
+            return self.receive_mode
+        else:
+            return self.website_mode
+
     def persistence_button_clicked(self):
         self.common.log("Tab", "persistence_button_clicked")
         if self.tab_settings["persistent"]:
@@ -531,13 +539,7 @@ class Tab(QtWidgets.QWidget):
         if self.tab_settings["persistent"]:
             dialog_text = strings._("gui_close_tab_warning_persistent_description")
         else:
-            if self.mode == self.common.gui.MODE_SHARE:
-                server_status = self.share_mode.server_status
-            elif self.mode == self.common.gui.MODE_RECEIVE:
-                server_status = self.receive_mode.server_status
-            else:
-                server_status = self.website_mode.server_status
-
+            server_status = self.get_mode().server_status
             if server_status.status == server_status.STATUS_STOPPED:
                 return True
             else:
@@ -566,14 +568,7 @@ class Tab(QtWidgets.QWidget):
         # Close
         if reply == 0:
             self.common.log("Tab", "close_tab", "close, closing tab")
-
-            if self.mode == self.common.gui.MODE_SHARE:
-                self.share_mode.stop_server()
-            elif self.mode == self.common.gui.MODE_RECEIVE:
-                self.receive_mode.stop_server()
-            else:
-                self.website_mode.stop_server()
-
+            self.get_mode().stop_server()
             self.app.cleanup()
             return True
         # Cancel
diff --git a/onionshare_gui/tab_widget.py b/onionshare_gui/tab_widget.py
index 73dea2bd..f9e48951 100644
--- a/onionshare_gui/tab_widget.py
+++ b/onionshare_gui/tab_widget.py
@@ -116,6 +116,16 @@ class TabWidget(QtWidgets.QTabWidget):
             if self.count() == 0:
                 self.new_tab_clicked()
 
+    def are_tabs_active(self):
+        """
+        See if there are active servers in any open tabs
+        """
+        for tab_id in self.tabs:
+            mode = self.tabs[tab_id].get_mode()
+            if mode.server_status.status != mode.server_status.STATUS_STOPPED:
+                return True
+        return False
+
     def resizeEvent(self, event):
         # Make sure to move new tab button on each resize
         super(TabWidget, self).resizeEvent(event)
diff --git a/share/locale/en.json b/share/locale/en.json
index 387e57b3..8948d317 100644
--- a/share/locale/en.json
+++ b/share/locale/en.json
@@ -30,11 +30,6 @@
     "gui_copied_hidservauth": "HidServAuth line copied to clipboard",
     "gui_waiting_to_start": "Scheduled to start in {}. Click to cancel.",
     "gui_please_wait": "Starting… Click to cancel.",
-    "gui_quit_title": "Not so fast",
-    "gui_share_quit_warning": "You're in the process of sending files. Are you sure you want to quit OnionShare?",
-    "gui_receive_quit_warning": "You're in the process of receiving files. Are you sure you want to quit OnionShare?",
-    "gui_quit_warning_quit": "Quit",
-    "gui_quit_warning_dont_quit": "Cancel",
     "error_rate_limit": "Someone has made too many wrong attempts to guess your password, so OnionShare has stopped the server. Start sharing again and send the recipient a new address to share.",
     "zip_progress_bar_format": "Compressing: %p%",
     "error_stealth_not_supported": "To use client authorization, you need at least both Tor 0.2.9.1-alpha (or Tor Browser 6.5) and python3-stem 1.5.0.",
@@ -194,5 +189,9 @@
     "gui_close_tab_warning_receive_description": "You're in the process of receiving files. Are you sure you want to close this tab?",
     "gui_close_tab_warning_website_description": "You're actively hosting a website. Are you sure you want to close this tab?",
     "gui_close_tab_warning_close": "Close",
-    "gui_close_tab_warning_cancel": "Cancel"
+    "gui_close_tab_warning_cancel": "Cancel",
+    "gui_quit_warning_title": "Are you sure?",
+    "gui_quit_warning_description": "Sharing is active in some of your tabs. If you quit, all of your tabs will close. Are you sure you want to quit?",
+    "gui_quit_warning_quit": "Quit",
+    "gui_quit_warning_cancel": "Cancel"
 }
\ No newline at end of file