diff --git a/doc/api/api_changes.rst b/doc/api/api_changes.rst
index 721e0549117c..d3bc6d242834 100644
--- a/doc/api/api_changes.rst
+++ b/doc/api/api_changes.rst
@@ -54,6 +54,10 @@ original location:
   'open-close-high-low' order of quotes, and what the module used and the later
   is 'open-high-low-close' order of quotes, which is the standard in finance.
 
+* The artist used to draw the outline of a `colorbar` has been changed
+  from a `matplotlib.lines.Line2D` to `matplotlib.patches.Polygon`,
+  thus `colorbar.ColorbarBase.outline` is now a
+  `matplotlib.patches.Polygon` object.
 
 .. _changes_in_1_3:
 
diff --git a/lib/matplotlib/colorbar.py b/lib/matplotlib/colorbar.py
index 20273a6f06fe..354d998a10d0 100644
--- a/lib/matplotlib/colorbar.py
+++ b/lib/matplotlib/colorbar.py
@@ -31,7 +31,6 @@
 import matplotlib.contour as contour
 import matplotlib.cm as cm
 import matplotlib.gridspec as gridspec
-import matplotlib.lines as lines
 import matplotlib.patches as mpatches
 import matplotlib.path as mpath
 import matplotlib.ticker as ticker
@@ -415,9 +414,12 @@ def _config_axes(self, X, Y):
         ax.set_ylim(*ax.dataLim.intervaly)
         if self.outline is not None:
             self.outline.remove()
-        self.outline = lines.Line2D(
-            xy[:, 0], xy[:, 1], color=mpl.rcParams['axes.edgecolor'],
-            linewidth=mpl.rcParams['axes.linewidth'])
+        self.outline = mpatches.Polygon(
+            xy, edgecolor=mpl.rcParams['axes.edgecolor'],
+            facecolor='none',
+            linewidth=mpl.rcParams['axes.linewidth'],
+            closed=True,
+            zorder=2)
         ax.add_artist(self.outline)
         self.outline.set_clip_box(None)
         self.outline.set_clip_path(None)