diff --git a/src/flake8/options/aggregator.py b/src/flake8/options/aggregator.py
index bdcd6a3..31adf9d 100644
--- a/src/flake8/options/aggregator.py
+++ b/src/flake8/options/aggregator.py
@@ -47,6 +47,10 @@ def aggregate_options(
     # Extend the default ignore value with the extended default ignore list,
     # registered by plugins.
     extended_default_ignore = manager.extended_default_ignore.copy()
+    # Let's store our extended default ignore for use by the decision engine
+    default_values.extended_default_ignore = (
+        manager.extended_default_ignore.copy()
+    )
     LOG.debug(
         "Extended default ignore list: %s", list(extended_default_ignore)
     )
diff --git a/src/flake8/style_guide.py b/src/flake8/style_guide.py
index 9be0fe8..91d21ab 100644
--- a/src/flake8/style_guide.py
+++ b/src/flake8/style_guide.py
@@ -166,7 +166,9 @@ class DecisionEngine(object):
                 reverse=True,
             )
         )
-        self.using_default_ignore = set(self.ignored) == set(defaults.IGNORE)
+        self.using_default_ignore = set(self.ignored) == set(
+            defaults.IGNORE
+        ).union(options.extended_default_ignore)
         self.using_default_select = set(self.selected) == set(defaults.SELECT)
 
     def _in_all_selected(self, code):  # type: (str) -> bool
diff --git a/tests/unit/test_decision_engine.py b/tests/unit/test_decision_engine.py
index 7d92309..ef77324 100644
--- a/tests/unit/test_decision_engine.py
+++ b/tests/unit/test_decision_engine.py
@@ -10,6 +10,7 @@ from flake8 import style_guide
 def create_options(**kwargs):
     """Create and return an instance of argparse.Namespace."""
     kwargs.setdefault('select', [])
+    kwargs.setdefault('extended_default_ignore', [])
     kwargs.setdefault('extended_default_select', [])
     kwargs.setdefault('ignore', [])
     kwargs.setdefault('extend_ignore', [])
@@ -144,54 +145,92 @@ def test_decision_for(select_list, ignore_list, extend_ignore, error_code,
 
 
 @pytest.mark.parametrize(
-    'select,ignore,extend_select,enabled_extensions,error_code,expected', [
-        (defaults.SELECT, [], ['I1'], [], 'I100',
+    'select,ignore,extended_default_ignore,extend_select,enabled_extensions,'
+    'error_code,expected', [
+        (defaults.SELECT, [], [], ['I1'], [], 'I100',
             style_guide.Decision.Selected),
-        (defaults.SELECT, [], ['I1'], [], 'I201',
+        (defaults.SELECT, [], [], ['I1'], [], 'I201',
             style_guide.Decision.Ignored),
-        (defaults.SELECT, ['I2'], ['I1'], [], 'I101',
+        (defaults.SELECT, ['I2'], [], ['I1'], [], 'I101',
             style_guide.Decision.Selected),
-        (defaults.SELECT, ['I2'], ['I1'], [], 'I201',
+        (defaults.SELECT, ['I2'], [], ['I1'], [], 'I201',
             style_guide.Decision.Ignored),
-        (defaults.SELECT, ['I1'], ['I10'], [], 'I101',
+        (defaults.SELECT, ['I1'], [], ['I10'], [], 'I101',
             style_guide.Decision.Selected),
-        (defaults.SELECT, ['I10'], ['I1'], [], 'I101',
+        (defaults.SELECT, ['I10'], [], ['I1'], [], 'I101',
             style_guide.Decision.Ignored),
-        (defaults.SELECT, [], [], ['U4'], 'U401',
+        (defaults.SELECT, [], [], [], ['U4'], 'U401',
             style_guide.Decision.Selected),
-        (defaults.SELECT, ['U401'], [], ['U4'], 'U401',
+        (defaults.SELECT, ['U401'], [], [], ['U4'], 'U401',
             style_guide.Decision.Ignored),
-        (defaults.SELECT, ['U401'], [], ['U4'], 'U402',
+        (defaults.SELECT, ['U401'], [], [], ['U4'], 'U402',
             style_guide.Decision.Selected),
-        (['E', 'W'], ['E13'], [], [], 'E131', style_guide.Decision.Ignored),
-        (['E', 'W'], ['E13'], [], [], 'E126', style_guide.Decision.Selected),
-        (['E2'], ['E21'], [], [], 'E221', style_guide.Decision.Selected),
-        (['E2'], ['E21'], [], [], 'E212', style_guide.Decision.Ignored),
-        (['F', 'W'], ['C90'], ['I1'], [], 'C901',
+        (
+            ['E', 'W'],
+            ['E13'],
+            [],
+            [],
+            [],
+            'E131',
+            style_guide.Decision.Ignored,
+        ),
+        (
+            ['E', 'W'],
+            ['E13'],
+            [],
+            [],
+            [],
+            'E126',
+            style_guide.Decision.Selected,
+        ),
+        (['E2'], ['E21'], [], [], [], 'E221', style_guide.Decision.Selected),
+        (['E2'], ['E21'], [], [], [], 'E212', style_guide.Decision.Ignored),
+        (['F', 'W'], ['C90'], [], ['I1'], [], 'C901',
             style_guide.Decision.Ignored),
-        (['E', 'W'], ['C'], [], [], 'E131',
+        (['E', 'W'], ['C'], [], [], [], 'E131',
             style_guide.Decision.Selected),
-        (defaults.SELECT, defaults.IGNORE, [], ['I'], 'I101',
+        (defaults.SELECT, defaults.IGNORE, [], [], ['I'], 'I101',
             style_guide.Decision.Selected),
-        (defaults.SELECT, defaults.IGNORE, ['G'], ['I'], 'G101',
+        (defaults.SELECT, defaults.IGNORE, [], ['G'], ['I'], 'G101',
             style_guide.Decision.Selected),
-        (defaults.SELECT, ['G1'], ['G'], ['I'], 'G101',
+        (defaults.SELECT, ['G1'], [], ['G'], ['I'], 'G101',
             style_guide.Decision.Ignored),
-        (defaults.SELECT, ['E126'], [], ['I'], 'I101',
+        (defaults.SELECT, ['E126'], [], [], ['I'], 'I101',
             style_guide.Decision.Selected),
-        (['E', 'W'], defaults.IGNORE, ['I'], [], 'I101',
+        (['E', 'W'], defaults.IGNORE, [], ['I'], [], 'I101',
             style_guide.Decision.Ignored),
+        (
+            ["E", "W", "I101"],
+            defaults.IGNORE + ("I101",),
+            ["I101"],
+            [],
+            [],
+            "I101",
+            style_guide.Decision.Selected,
+        ),
+        (
+            ["E", "W"],
+            defaults.IGNORE + ("I101",),
+            ["I101"],
+            [],
+            [],
+            "I101",
+            style_guide.Decision.Ignored,
+        ),
         # TODO(sigmavirus24) Figure out how to exercise the final catch-all
         # return statement
     ]
 )
-def test_more_specific_decision_for_logic(select, ignore, extend_select,
-                                          enabled_extensions, error_code,
-                                          expected):
+def test_more_specific_decision_for_logic(
+    select, ignore, extended_default_ignore, extend_select,
+    enabled_extensions, error_code,
+    expected,
+):
     """Verify the logic of DecisionEngine.more_specific_decision_for."""
     decider = style_guide.DecisionEngine(
         create_options(
             select=select, ignore=ignore,
+            extended_default_ignore=extended_default_ignore,
             extended_default_select=extend_select,
             enable_extensions=enabled_extensions,
         ),
diff --git a/tests/unit/test_style_guide.py b/tests/unit/test_style_guide.py
index 5503d7e..c24472a 100644
--- a/tests/unit/test_style_guide.py
+++ b/tests/unit/test_style_guide.py
@@ -13,6 +13,7 @@ from flake8.formatting import base
 def create_options(**kwargs):
     """Create and return an instance of argparse.Namespace."""
     kwargs.setdefault('select', [])
+    kwargs.setdefault('extended_default_ignore', [])
     kwargs.setdefault('extended_default_select', [])
     kwargs.setdefault('ignore', [])
     kwargs.setdefault('extend_ignore', [])