diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index 4bf9e15..60aad08 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -609,7 +609,7 @@ module ApplicationHelper
       parsed << text
       if tag
         if closing
-          if tags.last.casecmp(tag) == 0
+          if tags.last && tags.last.casecmp(tag) == 0
             tags.pop
           end
         else
diff --git a/test/unit/helpers/application_helper_test.rb b/test/unit/helpers/application_helper_test.rb
index 27c711d..883e9d3 100644
--- a/test/unit/helpers/application_helper_test.rb
+++ b/test/unit/helpers/application_helper_test.rb
@@ -994,6 +994,12 @@ EXPECTED
     assert_equal expected.gsub(%r{[\r\n\t]}, ''), textilizable(raw).gsub(%r{[\r\n\t]}, '')
   end
 
+  def test_unbalanced_closing_pre_tag_should_not_error
+    assert_nothing_raised do
+      textilizable("unbalanced</pre>")
+    end
+  end
+
   def test_syntax_highlight
     raw = <<-RAW
 <pre><code class="ruby">