diff --git a/documentation/ref-manual/variables.rst b/documentation/ref-manual/variables.rst
index 1fedb98d2..579faf7be 100644
--- a/documentation/ref-manual/variables.rst
+++ b/documentation/ref-manual/variables.rst
@@ -5893,6 +5893,13 @@ system and gives an overview of their function and contents.
       For the directory containing logs specific to each task, see the
       :term:`T` variable.
 
+   :term:`LTO`
+      The :term:`LTO` variable define the flags specific to the ``lto``
+      :term:`distro feature <DISTRO_FEATURES>`. The value of this variable is
+      appended to the :term:`TARGET_LDFLAGS` variable, adding `Link-Time
+      Optimisation <https://gcc.gnu.org/wiki/LinkTimeOptimization>`__ flags to
+      the linker in-use.
+
    :term:`MACHINE`
       Specifies the target device for which the image is built. You define
       :term:`MACHINE` in the ``local.conf`` file found in the