diff --git a/docs/Doxyfile b/docs/Doxyfile
index ef4976b..e04011a 100644
--- a/docs/Doxyfile
+++ b/docs/Doxyfile
@@ -1277,7 +1277,8 @@
 # instead of the = operator.
 
 PREDEFINED             = NS3_ASSERT_ENABLE \
-                         NS3_LOG_ENABLE
+                         NS3_LOG_ENABLE \
+                         DOXYGEN
 
 # If the MACRO_EXPANSION and EXPAND_ONLY_PREDEF tags are set to YES then
 # this tag can be used to specify a list of macro names that should be expanded.