diff --git a/lib/ex_doc/formatter/html/templates.ex b/lib/ex_doc/formatter/html/templates.ex
index 9515903c9..f4ed516f5 100644
--- a/lib/ex_doc/formatter/html/templates.ex
+++ b/lib/ex_doc/formatter/html/templates.ex
@@ -176,9 +176,9 @@ defmodule ExDoc.Formatter.HTML.Templates do
       |> Enum.map_join(",", &sidebar_items_by_type/1)
 
     if items == "" do
-      ~s/{"id":"#{module_node.id}","title":"#{module_node.title}","group":"#{module_node.group}"}/
+      ~s/{"id":#{inspect(module_node.id)},"title":#{inspect(module_node.title)},"group":"#{module_node.group}"}/
     else
-      ~s/{"id":"#{module_node.id}","title":"#{module_node.title}","group":"#{module_node.group}",#{items}}/
+      ~s/{"id":#{inspect(module_node.id)},"title":#{inspect(module_node.title)},"group":"#{module_node.group}",#{items}}/
     end
   end