diff -r 15b20201cfa5 Lib/shutil.py
--- a/Lib/shutil.py	Tue Apr 19 23:37:17 2016 +0300
+++ b/Lib/shutil.py	Wed Apr 20 00:14:52 2016 +0300
@@ -1072,7 +1072,7 @@ def get_terminal_size(fallback=(80, 24))
     if columns <= 0 or lines <= 0:
         try:
             size = os.get_terminal_size(sys.__stdout__.fileno())
-        except (AttributeError, OSError):
+        except (AttributeError, ValueError, OSError):
             size = os.terminal_size(fallback)
         if columns <= 0:
             columns = size.columns
diff -r 15b20201cfa5 Lib/test/test_shutil.py
--- a/Lib/test/test_shutil.py	Tue Apr 19 23:37:17 2016 +0300
+++ b/Lib/test/test_shutil.py	Wed Apr 20 00:14:52 2016 +0300
@@ -1836,6 +1836,14 @@ class TermsizeTests(unittest.TestCase):
             size = shutil.get_terminal_size()
         self.assertEqual(size.lines, 888)
 
+    def test_bad_environ(self):
+        with support.EnvironmentVarGuard() as env:
+            env['COLUMNS'] = 'xxx'
+            env['LINES'] = 'yyy'
+            size = shutil.get_terminal_size()
+        self.assertGreaterEqual(size.columns, 0)
+        self.assertGreaterEqual(size.lines, 0)
+
     @unittest.skipUnless(os.isatty(sys.__stdout__.fileno()), "not on tty")
     @unittest.skipUnless(hasattr(os, 'get_terminal_size'),
                          'need os.get_terminal_size()')
@@ -1859,6 +1867,31 @@ class TermsizeTests(unittest.TestCase):
 
         self.assertEqual(expected, actual)
 
+    def test_fallback(self):
+        with support.EnvironmentVarGuard() as env:
+            del env['LINES']
+            del env['COLUMNS']
+
+            # sys.__stdout__ has no fileno()
+            with support.swap_attr(sys, '__stdout__', None):
+                actual = shutil.get_terminal_size(fallback=(1, 2))
+            self.assertEqual(actual, (1, 2))
+
+            # sys.__stdout__.fileno() not in (0, 1, 2)
+            with open(os.devnull, 'w') as f, \
+                 support.swap_attr(sys, '__stdout__', f):
+                actual = shutil.get_terminal_size(fallback=(3, 4))
+            self.assertEqual(actual, (3, 4))
+
+            # No sys.__stdout__
+            with support.swap_attr(sys, '__stdout__', None):
+                try:
+                    del sys.__stdout__
+                    actual = shutil.get_terminal_size(fallback=(5, 6))
+                finally:
+                    sys.__stdout__ = None
+            self.assertEqual(actual, (5, 6))
+
 
 class PublicAPITests(unittest.TestCase):
     """Ensures that the correct values are exposed in the public API."""