2 files changed, 8 insertions, 1 deletions
diff --git a/activemodel/lib/active_model/error.rb b/activemodel/lib/active_model/error.rb
index 9731fa74df..5a1298e27f 100644
--- a/activemodel/lib/active_model/error.rb
+++ b/activemodel/lib/active_model/error.rb
@@ -64,7 +64,7 @@ module ActiveModel
     end
 
     def ==(other)
-      attributes_for_hash == other.attributes_for_hash
+      other.is_a?(self.class) && attributes_for_hash == other.attributes_for_hash
     end
     alias eql? ==
 
diff --git a/activemodel/test/cases/error_test.rb b/activemodel/test/cases/error_test.rb
index d1193d123f..d74321fee5 100644
--- a/activemodel/test/cases/error_test.rb
+++ b/activemodel/test/cases/error_test.rb
@@ -190,4 +190,11 @@ class ErrorTest < ActiveModel::TestCase
     assert error != ActiveModel::Error.new(person, :title, foo: :bar)
     assert error != ActiveModel::Error.new(Person.new, :name, foo: :bar)
   end
+
+  test "comparing against different class would not raise error" do
+    person = Person.new
+    error = ActiveModel::Error.new(person, :name, foo: :bar)
+
+    assert error != person
+  end
 end