diff --git a/lib/annotate/annotate_models.rb b/lib/annotate/annotate_models.rb
index 69da7e862..77cd77335 100644
--- a/lib/annotate/annotate_models.rb
+++ b/lib/annotate/annotate_models.rb
@@ -809,7 +809,7 @@ def annotate_model_file(annotated, file, header, options)
       begin
         return false if /#{SKIP_ANNOTATION_PREFIX}.*/ =~ (File.exist?(file) ? File.read(file) : '')
         klass = get_model_class(file)
-        do_annotate = klass &&
+        do_annotate = klass.is_a?(Class) &&
           klass < ActiveRecord::Base &&
           (!options[:exclude_sti_subclasses] || !(klass.superclass < ActiveRecord::Base && klass.table_name == klass.superclass.table_name)) &&
           !klass.abstract_class? &&
diff --git a/spec/lib/annotate/annotate_models_spec.rb b/spec/lib/annotate/annotate_models_spec.rb
index c3d0069e9..c9cab37af 100644
--- a/spec/lib/annotate/annotate_models_spec.rb
+++ b/spec/lib/annotate/annotate_models_spec.rb
@@ -2743,5 +2743,18 @@ class Foo < ActiveRecord::Base; end
     it 'skips attempt to annotate if no table exists for model' do
       is_expected.to eq nil
     end
+
+    context 'with a non-class' do
+      before do
+        NotAClass = 'foo'.freeze # rubocop:disable Naming/ConstantName
+        allow(AnnotateModels).to receive(:get_model_class).with('foo.rb') { NotAClass }
+      end
+
+      after { Object.send :remove_const, 'NotAClass' }
+
+      it "doesn't output an error" do
+        expect { subject }.not_to output.to_stderr
+      end
+    end
   end
 end