diff --git a/src/calibre/gui2/viewer/main.py b/src/calibre/gui2/viewer/main.py
index 170def8064..2b2323275e 100644
--- a/src/calibre/gui2/viewer/main.py
+++ b/src/calibre/gui2/viewer/main.py
@@ -169,7 +169,7 @@ def main(args=sys.argv):
     if opts.raise_window:
         main.raise_()
     if opts.full_screen:
-        main.showFullScreen()
+        main.set_full_screen(True)
 
     app.exec_()
     if listener is not None:
diff --git a/src/calibre/gui2/viewer/ui.py b/src/calibre/gui2/viewer/ui.py
index e59d2c3c1c..71de3ce9d0 100644
--- a/src/calibre/gui2/viewer/ui.py
+++ b/src/calibre/gui2/viewer/ui.py
@@ -11,7 +11,9 @@ from collections import defaultdict
 from hashlib import sha256
 from threading import Thread
 
-from PyQt5.Qt import QDockWidget, QModelIndex, Qt, QVBoxLayout, QWidget, pyqtSignal
+from PyQt5.Qt import (
+    QDockWidget, QEvent, QModelIndex, Qt, QVBoxLayout, QWidget, pyqtSignal
+)
 
 from calibre import prints
 from calibre.constants import config_dir
@@ -43,6 +45,7 @@ class EbookViewer(MainWindow):
 
     def __init__(self):
         MainWindow.__init__(self, None)
+        self.in_full_screen_mode = None
         try:
             os.makedirs(annotations_dir)
         except EnvironmentError:
@@ -73,11 +76,13 @@ class EbookViewer(MainWindow):
         self.web_view.reload_book.connect(self.reload_book)
         self.web_view.toggle_toc.connect(self.toggle_toc)
         self.web_view.update_current_toc_nodes.connect(self.toc.update_current_toc_nodes)
+        self.web_view.toggle_full_screen.connect(self.toggle_full_screen)
         self.setCentralWidget(self.web_view)
         state = vprefs['main_window_state']
         if state:
             self.restoreState(state, self.MAIN_WINDOW_STATE_VERSION)
 
+    # IPC {{{
     def handle_commandline_arg(self, arg):
         if arg:
             if os.path.isfile(arg) and os.access(arg, os.R_OK):
@@ -92,7 +97,28 @@ class EbookViewer(MainWindow):
             return
         self.load_ebook(path, open_at=open_at)
         self.raise_()
+    # }}}
 
+    # Fullscreen {{{
+    def set_full_screen(self, on):
+        if on:
+            self.showFullScreen()
+        else:
+            self.showNormal()
+
+    def changeEvent(self, ev):
+        if ev.type() == QEvent.WindowStateChange:
+            in_full_screen_mode = self.isFullScreen()
+            if self.in_full_screen_mode is None or self.in_full_screen_mode != in_full_screen_mode:
+                self.in_full_screen_mode = in_full_screen_mode
+                self.web_view.notify_full_screen_state_change(self.in_full_screen_mode)
+        return MainWindow.changeEvent(self, ev)
+
+    def toggle_full_screen(self):
+        self.set_full_screen(not self.isFullScreen())
+    # }}}
+
+    # ToC {{{
     def toggle_toc(self):
         if self.toc_dock.isVisible():
             self.toc_dock.setVisible(False)
@@ -106,6 +132,9 @@ class EbookViewer(MainWindow):
     def toc_searched(self, index):
         item = self.toc_model.itemFromIndex(index)
         self.web_view.goto_toc_node(item.node_id)
+    # }}}
+
+    # Load book {{{
 
     def load_ebook(self, pathtoebook, open_at=None, reload_book=False):
         # TODO: Implement open_at
@@ -166,7 +195,9 @@ class EbookViewer(MainWindow):
             with open(path, 'rb') as f:
                 raw = f.read()
             merge_annotations(parse_annotations(raw), amap)
+    # }}}
 
+    # CFI management {{{
     def initial_cfi_for_current_book(self):
         lrp = self.current_book_data['annotations_map']['last-read']
         if lrp:
@@ -179,7 +210,9 @@ class EbookViewer(MainWindow):
             return
         self.current_book_data['annotations_map']['last-read'] = [{
             'pos': cfi, 'pos_type': 'epubcfi', 'timestamp': utcnow()}]
+    # }}}
 
+    # State serialization {{{
     def save_annotations(self):
         if not self.current_book_data:
             return
@@ -201,3 +234,4 @@ class EbookViewer(MainWindow):
         self.save_annotations()
         self.save_state()
         return MainWindow.closeEvent(self, ev)
+    # }}}
diff --git a/src/calibre/gui2/viewer/web_view.py b/src/calibre/gui2/viewer/web_view.py
index 3608af430b..219e574122 100644
--- a/src/calibre/gui2/viewer/web_view.py
+++ b/src/calibre/gui2/viewer/web_view.py
@@ -171,11 +171,13 @@ class ViewerBridge(Bridge):
     reload_book = from_js()
     toggle_toc = from_js()
     update_current_toc_nodes = from_js(object, object)
+    toggle_full_screen = from_js()
 
     create_view = to_js()
     show_preparing_message = to_js()
     start_book_load = to_js()
     goto_toc_node = to_js()
+    full_screen_state_changed = to_js()
 
 
 class WebPage(QWebEnginePage):
@@ -252,6 +254,7 @@ class WebView(RestartingWebEngineView):
     reload_book = pyqtSignal()
     toggle_toc = pyqtSignal()
     update_current_toc_nodes = pyqtSignal(object, object)
+    toggle_full_screen = pyqtSignal()
 
     def __init__(self, parent=None):
         self._host_widget = None
@@ -267,6 +270,7 @@ class WebView(RestartingWebEngineView):
         self.bridge.reload_book.connect(self.reload_book)
         self.bridge.toggle_toc.connect(self.toggle_toc)
         self.bridge.update_current_toc_nodes.connect(self.update_current_toc_nodes)
+        self.bridge.toggle_full_screen.connect(self.toggle_full_screen)
         self.pending_bridge_ready_actions = {}
         self.setPage(self._page)
         self.setAcceptDrops(False)
@@ -343,6 +347,9 @@ class WebView(RestartingWebEngineView):
     def goto_toc_node(self, node_id):
         self.execute_when_ready('goto_toc_node', node_id)
 
+    def notify_full_screen_state_change(self, in_fullscreen_mode):
+        self.execute_when_ready('full_screen_state_changed', in_fullscreen_mode)
+
     def set_session_data(self, key, val):
         if key == '*' and val is None:
             vprefs['session_data'] = {}
diff --git a/src/pyj/read_book/globals.pyj b/src/pyj/read_book/globals.pyj
index 51b44619c3..882800c4a2 100644
--- a/src/pyj/read_book/globals.pyj
+++ b/src/pyj/read_book/globals.pyj
@@ -62,7 +62,8 @@ register_callback(def():
 )
 
 runtime = {
-    'is_standalone_viewer': False
+    'is_standalone_viewer': False,
+    'viewer_in_full_screen': False,
 }
 
 
diff --git a/src/pyj/read_book/overlay.pyj b/src/pyj/read_book/overlay.pyj
index 36a9398500..e069b81f0e 100644
--- a/src/pyj/read_book/overlay.pyj
+++ b/src/pyj/read_book/overlay.pyj
@@ -216,17 +216,18 @@ class MainOverlay:
         sync_action = ac(_('Sync'), _('Get last read position and annotations from the server'), self.overlay.sync_book, 'cloud-download')
         delete_action = ac(_('Delete'), _('Delete this book from the device'), self.overlay.delete_book, 'trash')
         reload_action = ac(_('Reload'), _('Reload this book from the {}').format( _('computer') if runtime.is_standalone_viewer else _('server')), self.overlay.reload_book, 'refresh')
+        home_action = ac(_('Home'), _('Return to list of books'), def(): home();, 'home')
+        back_action = ac(_('Back'), None, self.back, 'arrow-left')
+        forward_action = ac(_('Forward'), None, self.forward, 'arrow-right')
         if runtime.is_standalone_viewer:
             reload_actions = E.ul(reload_action)
+            nav_actions = E.ul(back_action, forward_action)
         else:
             reload_actions = E.ul(sync_action, delete_action, reload_action)
+            nav_actions = E.ul(home_action, back_action, forward_action)
 
         actions_div = E.div( # actions
-            E.ul(
-                ac(_('Home'), _('Return to list of books'), def(): home();, 'home'),
-                ac(_('Back'), None, self.back, 'arrow-left'),
-                ac(_('Forward'), None, self.forward, 'arrow-right'),
-            ),
+            nav_actions,
 
             E.ul(
                 ac(_('Search'), _('Search for text in this book'), self.overlay.show_search, 'search'),
@@ -247,12 +248,19 @@ class MainOverlay:
 
             class_=MAIN_OVERLAY_ACTIONS_CLASS
         )
-        if not full_screen_element() and not is_ios:
-            # No fullscreen on iOS, see http://caniuse.com/#search=fullscreen
-            actions_div.appendChild(
-            E.ul(
-                ac(_('Full screen'), _('Enter full screen mode'), def(): request_full_screen(), self.overlay.hide();, 'full-screen'),
-            ))
+        full_screen_actions = []
+        if runtime.is_standalone_viewer:
+            text = _('Exit full screen') if runtime.viewer_in_full_screen else _('Enter full screen')
+            full_screen_actions.push(
+                ac(text, '', def(): self.overlay.hide(), ui_operations.toggle_full_screen();, 'full-screen'))
+        else:
+            if not full_screen_element() and not is_ios:
+                # No fullscreen on iOS, see http://caniuse.com/#search=fullscreen
+                full_screen_actions.push(
+                    ac(_('Full screen'), _('Enter full screen mode'), def(): request_full_screen(), self.overlay.hide();, 'full-screen')
+                )
+        if full_screen_actions.length:
+            actions_div.appendChild(E.ul(*full_screen_actions))
 
         container.appendChild(set_css(E.div(class_=MAIN_OVERLAY_TS_CLASS,  # top section
             onclick=def (evt):evt.stopPropagation();,
diff --git a/src/pyj/viewer-main.pyj b/src/pyj/viewer-main.pyj
index 53eedf09b6..8af6a76639 100644
--- a/src/pyj/viewer-main.pyj
+++ b/src/pyj/viewer-main.pyj
@@ -198,6 +198,11 @@ def goto_toc_node(node_id):
     view.goto_toc_node(node_id)
 
 
+@from_python
+def full_screen_state_changed(viewer_in_full_screen):
+    runtime.viewer_in_full_screen = viewer_in_full_screen
+
+
 def onerror(msg, script_url, line_number, column_number, error_object):
     if not error_object:
         # cross domain error
@@ -246,6 +251,8 @@ if window is window.top:
         to_python.toggle_toc()
     ui_operations.update_current_toc_nodes = def(current_node_id, top_level_node_id):
         to_python.update_current_toc_nodes(current_node_id, top_level_node_id)
+    ui_operations.toggle_full_screen = def():
+        to_python.toggle_full_screen()
     document.body.appendChild(E.div(id='view'))
     window.onerror = onerror
     create_modal_container()