diff --git a/src/calibre/gui2/viewer/toc.py b/src/calibre/gui2/viewer/toc.py
index 10481370fb..633ad0105a 100644
--- a/src/calibre/gui2/viewer/toc.py
+++ b/src/calibre/gui2/viewer/toc.py
@@ -148,7 +148,8 @@ class TOCSearch(QWidget):
     def do_search(self, text):
         if not text or not text.strip():
             return
-        index = self.toc_view.model().search(text)
+        delta = -1 if QApplication.instance().keyboardModifiers() & Qt.KeyboardModifier.ShiftModifier else 1
+        index = self.toc_view.model().search(text, delta=delta)
         if index.isValid():
             self.toc_view.scrollTo(index)
             self.toc_view.searched.emit(index)
@@ -244,15 +245,16 @@ class TOC(QStandardItemModel):
             if (exact and query == href) or (not exact and query in href):
                 return item.node_id
 
-    def search(self, query):
+    def search(self, query, delta=1):
         cq = self.current_query
         if cq['items'] and -1 < cq['index'] < len(cq['items']):
             cq['items'][cq['index']].set_current_search_result(False)
         if cq['text'] != query:
             items = tuple(self.find_items(query))
             cq.update({'text':query, 'items':items, 'index':-1})
-        if len(cq['items']) > 0:
-            cq['index'] = (cq['index'] + 1) % len(cq['items'])
+        num = len(cq['items'])
+        if num > 0:
+            cq['index'] = (cq['index'] + delta + num) % num
             item = cq['items'][cq['index']]
             item.set_current_search_result(True)
             index = self.indexFromItem(item)