diff --git a/documentation/ref-manual/variables.rst b/documentation/ref-manual/variables.rst
index 5aead5ff21..b644a0a787 100644
--- a/documentation/ref-manual/variables.rst
+++ b/documentation/ref-manual/variables.rst
@@ -5385,6 +5385,13 @@ system and gives an overview of their function and contents.
       default by setting the variable in a custom distribution
       configuration file.
 
+   :term:`OPKGBUILDCMD`
+      The variable :term:`OPKGBUILDCMD` specifies the command used to build opkg
+      packages when using the :ref:`ref-classes-package_ipk` class. It is
+      defined in :ref:`ref-classes-package_ipk` as::
+
+          OPKGBUILDCMD ??= 'opkg-build -Z zstd -a "${ZSTD_DEFAULTS}"'
+
    :term:`OVERRIDES`
       A colon-separated list of overrides that currently apply. Overrides
       are a BitBake mechanism that allows variables to be selectively