diff --git a/doc/source/merging.rst b/doc/source/merging.rst
index ebade853313ab..4d9746eed0f0b 100644
--- a/doc/source/merging.rst
+++ b/doc/source/merging.rst
@@ -323,6 +323,13 @@ the name of the ``Series``.
           labels=['df1', 's1'], vertical=False);
    plt.close('all');
 
+.. note::
+
+   Since we're concatenating a ``Series`` to a ``DataFrame``, we could have
+   achieved the same result with :meth:`DataFrame.assign`. To concatenate an
+   arbitrary number of pandas objects (``DataFrame`` or ``Series``), use
+   ``concat``.
+
 If unnamed ``Series`` are passed they will be numbered consecutively.
 
 .. ipython:: python
diff --git a/doc/source/whatsnew/v0.23.0.txt b/doc/source/whatsnew/v0.23.0.txt
index 879b245af49cd..8d6a3dc72163e 100644
--- a/doc/source/whatsnew/v0.23.0.txt
+++ b/doc/source/whatsnew/v0.23.0.txt
@@ -677,7 +677,7 @@ Documentation Changes
   Rewrote some sentences for greater clarity, added more dynamic references
   to functions, methods and classes.
   (:issue:`18941`, :issue:`18948`, :issue:`18973`, :issue:`19017`)
-
+- Added a reference to :func:`DataFrame.assign` in the concatenate section of the merging documentation (:issue:`18665`)
 
 .. _whatsnew_0230.bug_fixes: