diff --git a/doc/threadsafety.rst b/doc/threadsafety.rst
index bea5978..d9b881a 100644
--- a/doc/threadsafety.rst
+++ b/doc/threadsafety.rst
@@ -61,7 +61,7 @@ program startup. See :ref:`apiref-custom-memory-allocation`.
 
 
 Locale
-------
+======
 
 Jansson works fine under any locale.