diff --git a/Doc/library/functools.rst b/Doc/library/functools.rst
index 221c0712c7c96a..89f2265deb56ec 100644
--- a/Doc/library/functools.rst
+++ b/Doc/library/functools.rst
@@ -718,6 +718,11 @@ The :mod:`functools` module defines the following functions:
    The same pattern can be used for other similar decorators:
    :deco:`staticmethod`, :deco:`~abc.abstractmethod`, and others.
 
+    For every ``singledispatchmethod`` method defined in a class, the value
+    dispatched on by that method is *always* the first argument passed for the call.
+    Therefore, dispatching to regular methods can only be sensibly performed by
+    calling such a method from instances of the class, and not from the class object.
+
    .. versionadded:: 3.8
 
    .. versionchanged:: 3.15