diff --git a/src/calibre/gui2/viewer/config.py b/src/calibre/gui2/viewer/config.py
index 99cceee265..f45587d248 100644
--- a/src/calibre/gui2/viewer/config.py
+++ b/src/calibre/gui2/viewer/config.py
@@ -47,6 +47,8 @@ def config(defaults=None):
     c.add_opt('hyphenate', default=False, help=_('Hyphenate text'))
     c.add_opt('hyphenate_default_lang', default='en',
             help=_('Default language for hyphenation rules'))
+    c.add_opt('search_online_url', default='https://www.google.com/search?q={text}',
+              help=_('The URL to use when searching for selected text online'))
     c.add_opt('remember_current_page', default=True,
             help=_('Save the current position in the document, when quitting'))
     c.add_opt('copy_bookmarks_to_file', default=True,
@@ -313,6 +315,7 @@ class ConfigDialog(QDialog, Ui_Dialog):
         self.hyphenate_default_lang.setCurrentIndex(idx)
         self.hyphenate.setChecked(opts.hyphenate)
         self.hyphenate_default_lang.setEnabled(opts.hyphenate)
+        self.search_online_url.setText(opts.search_online_url or '')
         self.opt_fit_images.setChecked(opts.fit_images)
         self.opt_fullscreen_clock.setChecked(opts.fullscreen_clock)
         self.opt_fullscreen_scrollbar.setChecked(opts.fullscreen_scrollbar)
@@ -397,6 +400,7 @@ class ConfigDialog(QDialog, Ui_Dialog):
                 self.hyphenate_default_lang.itemData(idx))
         c.set('line_scrolling_stops_on_pagebreaks',
                 self.opt_line_scrolling_stops_on_pagebreaks.isChecked())
+        c.set('search_online_url', self.search_online_url.text().strip())
         c.set('fullscreen_clock', self.opt_fullscreen_clock.isChecked())
         c.set('fullscreen_pos', self.opt_fullscreen_pos.isChecked())
         c.set('fullscreen_scrollbar', self.opt_fullscreen_scrollbar.isChecked())
diff --git a/src/calibre/gui2/viewer/config.ui b/src/calibre/gui2/viewer/config.ui
index 7783072187..124c8b3b80 100644
--- a/src/calibre/gui2/viewer/config.ui
+++ b/src/calibre/gui2/viewer/config.ui
@@ -240,8 +240,8 @@ QToolBox::tab:hover {
            <rect>
             <x>0</x>
             <y>0</y>
-            <width>374</width>
-            <height>211</height>
+            <width>799</width>
+            <height>378</height>
            </rect>
           </property>
           <attribute name="label">
@@ -370,8 +370,8 @@ QToolBox::tab:hover {
            <rect>
             <x>0</x>
             <y>0</y>
-            <width>381</width>
-            <height>193</height>
+            <width>799</width>
+            <height>378</height>
            </rect>
           </property>
           <attribute name="label">
@@ -472,8 +472,8 @@ QToolBox::tab:hover {
            <rect>
             <x>0</x>
             <y>0</y>
-            <width>340</width>
-            <height>70</height>
+            <width>799</width>
+            <height>378</height>
            </rect>
           </property>
           <attribute name="label">
@@ -551,8 +551,8 @@ QToolBox::tab:hover {
            <rect>
             <x>0</x>
             <y>0</y>
-            <width>384</width>
-            <height>140</height>
+            <width>799</width>
+            <height>378</height>
            </rect>
           </property>
           <attribute name="label">
@@ -636,7 +636,38 @@ QToolBox::tab:hover {
           <attribute name="label">
            <string>&amp;Miscellaneous options</string>
           </attribute>
-          <layout class="QFormLayout" name="formLayout_4">
+          <layout class="QGridLayout" name="gridLayout">
+           <item row="4" column="0" colspan="2">
+            <widget class="QCheckBox" name="opt_remember_window_size">
+             <property name="text">
+              <string>Remember last used &amp;window size and layout</string>
+             </property>
+            </widget>
+           </item>
+           <item row="5" column="0" colspan="2">
+            <widget class="QCheckBox" name="opt_remember_current_page">
+             <property name="text">
+              <string>Remember the &amp;current page when quitting</string>
+             </property>
+            </widget>
+           </item>
+           <item row="6" column="0" colspan="2">
+            <widget class="QCheckBox" name="opt_copy_bookmarks_to_file">
+             <property name="toolTip">
+              <string>Keep a copy of all bookmarks/current page information inside the ebook file, so that you can share them by simply sending the ebook file itself. Currently only works with ebooks in the EPUB format.</string>
+             </property>
+             <property name="text">
+              <string>Keep a copy of bookmarks/current page inside the ebook file, for easy sharing</string>
+             </property>
+            </widget>
+           </item>
+           <item row="2" column="0" colspan="2">
+            <widget class="QCheckBox" name="opt_show_controls">
+             <property name="text">
+              <string>Show &amp;controls in the viewer window</string>
+             </property>
+            </widget>
+           </item>
            <item row="0" column="0" colspan="2">
             <widget class="QCheckBox" name="hyphenate">
              <property name="text">
@@ -644,6 +675,13 @@ QToolBox::tab:hover {
              </property>
             </widget>
            </item>
+           <item row="7" column="0">
+            <widget class="QPushButton" name="clear_search_history_button">
+             <property name="text">
+              <string>Clear search history</string>
+             </property>
+            </widget>
+           </item>
            <item row="1" column="0">
             <widget class="QLabel" name="hyphenate_label">
              <property name="text">
@@ -661,44 +699,38 @@ QToolBox::tab:hover {
              </property>
             </widget>
            </item>
-           <item row="6" column="0">
-            <widget class="QPushButton" name="clear_search_history_button">
-             <property name="text">
-              <string>Clear search history</string>
-             </property>
-            </widget>
-           </item>
-           <item row="2" column="0">
-            <widget class="QCheckBox" name="opt_show_controls">
-             <property name="text">
-              <string>Show &amp;controls in the viewer window</string>
-             </property>
-            </widget>
-           </item>
            <item row="3" column="0">
-            <widget class="QCheckBox" name="opt_remember_window_size">
+            <widget class="QLabel" name="label_26">
              <property name="text">
-              <string>Remember last used &amp;window size and layout</string>
+              <string>&amp;Search online URL:</string>
+             </property>
+             <property name="buddy">
+              <cstring>search_online_url</cstring>
              </property>
             </widget>
            </item>
-           <item row="4" column="0">
-            <widget class="QCheckBox" name="opt_remember_current_page">
-             <property name="text">
-              <string>Remember the &amp;current page when quitting</string>
-             </property>
-            </widget>
-           </item>
-           <item row="5" column="0" colspan="2">
-            <widget class="QCheckBox" name="opt_copy_bookmarks_to_file">
+           <item row="3" column="1">
+            <widget class="QLineEdit" name="search_online_url">
              <property name="toolTip">
-              <string>Keep a copy of all bookmarks/current page information inside the ebook file, so that you can share them by simply sending the ebook file itself. Currently only works with ebooks in the EPUB format.</string>
-             </property>
-             <property name="text">
-              <string>Keep a copy of bookmarks/current page inside the ebook file, for easy sharing</string>
+              <string>Change the search engine used to perform online searches for selected text.
+You must enter the search URL for the search engine, with the placeholder
+{text}, which will be replaced by the selected text.</string>
              </property>
             </widget>
            </item>
+           <item row="8" column="0">
+            <spacer name="verticalSpacer">
+             <property name="orientation">
+              <enum>Qt::Vertical</enum>
+             </property>
+             <property name="sizeHint" stdset="0">
+              <size>
+               <width>20</width>
+               <height>40</height>
+              </size>
+             </property>
+            </spacer>
+           </item>
           </layout>
          </widget>
         </widget>
diff --git a/src/calibre/gui2/viewer/documentview.py b/src/calibre/gui2/viewer/documentview.py
index b4cf1aedd2..d57d7d27e9 100644
--- a/src/calibre/gui2/viewer/documentview.py
+++ b/src/calibre/gui2/viewer/documentview.py
@@ -189,6 +189,7 @@ class Document(QWebPage):  # {{{
         self.show_controls = opts.show_controls
         self.remember_current_page = opts.remember_current_page
         self.copy_bookmarks_to_file = opts.copy_bookmarks_to_file
+        self.search_online_url = opts.search_online_url or 'https://www.google.com/search?q={text}'
 
     def fit_images(self):
         if self.do_fit_images and not self.in_paged_mode:
@@ -701,7 +702,7 @@ class DocumentView(QWebView):  # {{{
         if len(t) > 40:
             t = t[:40] + u'...'
         t = t.replace(u'&', u'&&')
-        return _("S&earch Google for '%s'")%t
+        return _("S&earch online for '%s'")%t
 
     def popup_table(self):
         html = self.document.extract_node()
@@ -820,7 +821,7 @@ class DocumentView(QWebView):  # {{{
             self.do_search_online(t)
 
     def do_search_online(self, text):
-        url = 'https://www.google.com/search?q=' + QUrl().toPercentEncoding(text)
+        url = self.document.search_online_url.replace('{text}', QUrl().toPercentEncoding(text))
         open_url(QUrl.fromEncoded(url))
 
     def set_manager(self, manager):