diff --git a/src/calibre/gui2/viewer/documentview.py b/src/calibre/gui2/viewer/documentview.py
index 170fb936bd..7f3ab26ec0 100644
--- a/src/calibre/gui2/viewer/documentview.py
+++ b/src/calibre/gui2/viewer/documentview.py
@@ -956,6 +956,13 @@ class DocumentView(QWebView): # {{{
         painter.end()
 
     def wheelEvent(self, event):
+        mods = event.modifiers()
+        if mods & Qt.CTRL:
+            if self.manager is not None and event.delta() != 0:
+                f = (self.manager.font_size_larger if event.delta() > 0 else
+                        self.manager.font_size_smaller)
+                f(False)
+            return
         if event.delta() < -14:
             if self.document.wheel_flips_pages:
                 self.next_page()