diff --git a/doc/users/whats_new/style_changes.rst b/doc/users/whats_new/style_changes.rst
index 5116f1bc12e..c1152e6bba0 100644
--- a/doc/users/whats_new/style_changes.rst
+++ b/doc/users/whats_new/style_changes.rst
@@ -28,6 +28,13 @@ Colors
 - Grid lines are light grey solid 1pt lines.  They are no longer dashed by
   default.
 
+Plots
+`````
+
+- The default size of the elements in a scatter plot is now based on
+  the rcParam ``lines.markersize`` so it is consistent with ``plot(X,
+  Y, 'o')``.  The old value was 20, and the new value is 36 (6^2).
+
 Plot layout
 ```````````
 
diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
index 49d755ae195..e695b32baa1 100644
--- a/lib/matplotlib/axes/_axes.py
+++ b/lib/matplotlib/axes/_axes.py
@@ -3726,7 +3726,7 @@ def dopatch(xs, ys, **kwargs):
                                         'facecolors', 'color'],
                          label_namer="y")
     @docstring.dedent_interpd
-    def scatter(self, x, y, s=20, c=None, marker='o', cmap=None, norm=None,
+    def scatter(self, x, y, s=None, c=None, marker='o', cmap=None, norm=None,
                 vmin=None, vmax=None, alpha=None, linewidths=None,
                 verts=None, edgecolors=None,
                 **kwargs):
@@ -3739,8 +3739,8 @@ def scatter(self, x, y, s=20, c=None, marker='o', cmap=None, norm=None,
         x, y : array_like, shape (n, )
             Input data
 
-        s : scalar or array_like, shape (n, ), optional, default: 20
-            size in points^2.
+        s : scalar or array_like, shape (n, ), optional
+            size in points^2.  Default is `rcParams['lines.markersize'] ** 2`.
 
         c : color, sequence, or sequence of color, optional, default: 'b'
             `c` can be a single color format string, or a sequence of color
@@ -3861,6 +3861,12 @@ def scatter(self, x, y, s=20, c=None, marker='o', cmap=None, norm=None,
         if x.size != y.size:
             raise ValueError("x and y must be the same size")
 
+        if s is None:
+            if rcParams['_internal.classic_mode']:
+                s = 20
+            else:
+                s = rcParams['lines.markersize'] ** 2.0
+
         s = np.ma.ravel(s)  # This doesn't have to match x, y in size.
 
         # After this block, c_array will be None unless
diff --git a/lib/matplotlib/pyplot.py b/lib/matplotlib/pyplot.py
index 5ea396df7df..9b3dd9ea81b 100644
--- a/lib/matplotlib/pyplot.py
+++ b/lib/matplotlib/pyplot.py
@@ -3138,7 +3138,7 @@ def quiverkey(*args, **kw):
 # This function was autogenerated by boilerplate.py.  Do not edit as
 # changes will be lost
 @_autogen_docstring(Axes.scatter)
-def scatter(x, y, s=20, c=None, marker='o', cmap=None, norm=None, vmin=None,
+def scatter(x, y, s=None, c=None, marker='o', cmap=None, norm=None, vmin=None,
             vmax=None, alpha=None, linewidths=None, verts=None, edgecolors=None,
             hold=None, data=None, **kwargs):
     ax = gca()