diff --git a/activerecord/lib/active_record/core.rb b/activerecord/lib/active_record/core.rb
index 1250f8a3c3cc1361044ac3b18521d620169061d5..475a298467557bf3faddb4f3314faf430fcb4364 100644
--- a/activerecord/lib/active_record/core.rb
+++ b/activerecord/lib/active_record/core.rb
@@ -275,7 +275,7 @@ def cached_find_by_statement(key, &block) # :nodoc:
       def relation # :nodoc:
         relation = Relation.create(self, arel_table, predicate_builder)
 
-        if finder_needs_type_condition?
+        if finder_needs_type_condition? && !ignore_default_scope?
           relation.where(type_condition).create_with(inheritance_column.to_sym => sti_name)
         else
           relation
diff --git a/activerecord/lib/active_record/scoping/default.rb b/activerecord/lib/active_record/scoping/default.rb
index cdcb73382ffaefe8f41362db06d0227bfa527b0e..8baf3b80449c8dc6c8e5376c432c65e2040f01c7 100644
--- a/activerecord/lib/active_record/scoping/default.rb
+++ b/activerecord/lib/active_record/scoping/default.rb
@@ -122,11 +122,11 @@ def build_default_scope(base_rel = nil) # :nodoc:
         end
 
         def ignore_default_scope? # :nodoc:
-          ScopeRegistry.value_for(:ignore_default_scope, self)
+          ScopeRegistry.value_for(:ignore_default_scope, base_class)
         end
 
         def ignore_default_scope=(ignore) # :nodoc:
-          ScopeRegistry.set_value_for(:ignore_default_scope, self, ignore)
+          ScopeRegistry.set_value_for(:ignore_default_scope, base_class, ignore)
         end
 
         # The ignore_default_scope flag is used to prevent an infinite recursion
diff --git a/activerecord/test/cases/scoping/default_scoping_test.rb b/activerecord/test/cases/scoping/default_scoping_test.rb
index 86316ab47691c7d29c5460da12a88dd0cee1a244..ad5ca70f3641b8d6e43272f5fb9c17bf76a46f19 100644
--- a/activerecord/test/cases/scoping/default_scoping_test.rb
+++ b/activerecord/test/cases/scoping/default_scoping_test.rb
@@ -459,4 +459,18 @@ def test_with_abstract_class_where_clause_should_not_be_duplicated
     scope = Bus.all
     assert_equal scope.where_clause.ast.children.length, 1
   end
+
+  def test_sti_conditions_are_not_carried_in_default_scope
+    ConditionalStiPost.create! body: ''
+    SubConditionalStiPost.create! body: ''
+    SubConditionalStiPost.create! title: 'Hello world', body: ''
+
+    assert_equal 2, ConditionalStiPost.count
+    assert_equal 2, ConditionalStiPost.all.to_a.size
+    assert_equal 3, ConditionalStiPost.unscope(where: :title).to_a.size
+
+    assert_equal 1, SubConditionalStiPost.count
+    assert_equal 1, SubConditionalStiPost.all.to_a.size
+    assert_equal 2, SubConditionalStiPost.unscope(where: :title).to_a.size
+  end
 end
diff --git a/activerecord/test/models/post.rb b/activerecord/test/models/post.rb
index 23cebe2602c270f63c92675a53795e34f6437696..bf3079a1dffd39747dce117c355e2fed3e4e11e8 100644
--- a/activerecord/test/models/post.rb
+++ b/activerecord/test/models/post.rb
@@ -263,3 +263,10 @@ class PostWithCommentWithDefaultScopeReferencesAssociation < ActiveRecord::Base
 class SerializedPost < ActiveRecord::Base
   serialize :title
 end
+
+class ConditionalStiPost < Post
+  default_scope { where(title: 'Untitled') }
+end
+
+class SubConditionalStiPost < ConditionalStiPost
+end