diff --git a/src/libstrongswan/library.h b/src/libstrongswan/library.h
index b1c577855..b1da19b45 100644
--- a/src/libstrongswan/library.h
+++ b/src/libstrongswan/library.h
@@ -19,6 +19,9 @@
  * @defgroup asn1 asn1
  * @ingroup libstrongswan
  *
+ * @defgroup bio bio
+ * @ingroup libstrongswan
+ *
  * @defgroup credentials credentials
  * @ingroup libstrongswan
  *