diff --git a/lib/matplotlib/figure.py b/lib/matplotlib/figure.py
index 385395c0d448..6fdf1265ff3b 100644
--- a/lib/matplotlib/figure.py
+++ b/lib/matplotlib/figure.py
@@ -2092,6 +2092,12 @@ def subplots_adjust(self, left=None, bottom=None, right=None, top=None,
         *None*) and update the subplot locations.
 
         """
+        if self.get_constrained_layout():
+            self.set_constrained_layout(False)
+            warnings.warn("This figure was using constrained_layout==True, "
+                          "but that is incompatible with subplots_adjust and "
+                          "or tight_layout: setting "
+                          "constrained_layout==False. ")
         self.subplotpars.update(left, bottom, right, top, wspace, hspace)
         for ax in self.axes:
             if not isinstance(ax, SubplotBase):
diff --git a/lib/matplotlib/tests/test_figure.py b/lib/matplotlib/tests/test_figure.py
index d0079012a5e6..de5a6c8aa0dd 100644
--- a/lib/matplotlib/tests/test_figure.py
+++ b/lib/matplotlib/tests/test_figure.py
@@ -373,6 +373,14 @@ def test_figure_repr():
     assert repr(fig) == "<Figure size 100x200 with 0 Axes>"
 
 
+def test_warn_cl_plus_tl():
+    fig, ax = plt.subplots(constrained_layout=True)
+    with pytest.warns(UserWarning):
+        # this should warn,
+        fig.subplots_adjust(top=0.8)
+    assert not(fig.get_constrained_layout())
+
+
 @pytest.mark.skipif(sys.version_info < (3, 6), reason="requires Python 3.6+")
 @pytest.mark.parametrize("fmt", ["png", "pdf", "ps", "eps", "svg"])
 def test_fspath(fmt, tmpdir):