diff --git a/pkg/libfixmath/doc.txt b/pkg/libfixmath/doc.txt
index 34caa8fecb..1871b992b8 100644
--- a/pkg/libfixmath/doc.txt
+++ b/pkg/libfixmath/doc.txt
@@ -1,7 +1,7 @@
 /**
  * @defgroup pkg_libfixmath Cross platform fixed point maths library
  * @ingroup  pkg
- * @ingroup  sys
+ * @ingroup  sys_math
  * @brief    Provides a cross platform fixed point maths library to RIOT.
  * @see      https://github.com/PetteriAimonen/libfixmath
- */
\ No newline at end of file
+ */