diff --git a/lib/pronto/runner.rb b/lib/pronto/runner.rb
index 2f232eed..a22c5e03 100644
--- a/lib/pronto/runner.rb
+++ b/lib/pronto/runner.rb
@@ -21,6 +21,7 @@ def rake_file?(path)
     end
 
     def ruby_executable?(path)
+      return false if File.directory?(path)
       line = File.open(path, &:readline)
       line =~ /#!.*ruby/
     rescue ArgumentError, EOFError
diff --git a/spec/pronto/runner_spec.rb b/spec/pronto/runner_spec.rb
index aa4f1379..8866b72d 100644
--- a/spec/pronto/runner_spec.rb
+++ b/spec/pronto/runner_spec.rb
@@ -34,6 +34,12 @@ module Pronto
           it { should be_falsy }
         end
       end
+
+      context 'directory' do
+        let(:path) { 'directory' }
+        before { File.stub(:directory?).with(path).and_return(true) }
+        it { should be_falsy }
+      end
     end
   end
 end