diff --git a/plugins/provisioners/ansible/provisioner/base.rb b/plugins/provisioners/ansible/provisioner/base.rb
index 51377a61f..981cbf5d1 100644
--- a/plugins/provisioners/ansible/provisioner/base.rb
+++ b/plugins/provisioners/ansible/provisioner/base.rb
@@ -71,7 +71,12 @@ module VagrantPlugins
         end
 
         def get_inventory_host_vars_string(machine_name)
-          vars = config.host_vars[machine_name]
+          # In Ruby, Symbol and String values are different, but
+          # Vagrant has to unify them for better user experience.
+          vars = config.host_vars[machine_name.to_sym]
+          if !vars
+            vars = config.host_vars[machine_name.to_s]
+          end
           s = nil
           if vars.is_a?(Hash)
             s = vars.each.collect{ |k, v| "#{k}=#{v}" }.join(" ")
diff --git a/test/unit/plugins/provisioners/ansible/provisioner_test.rb b/test/unit/plugins/provisioners/ansible/provisioner_test.rb
index cd76d68f8..4a352a29e 100644
--- a/test/unit/plugins/provisioners/ansible/provisioner_test.rb
+++ b/test/unit/plugins/provisioners/ansible/provisioner_test.rb
@@ -246,6 +246,16 @@ VF
           expect(inventory_content).to match("^" + Regexp.quote(machine.name) + ".+http_port=80 maxRequestsPerChild=808")
         }
       end
+
+      it "retrieves the host variables by machine name, also in String format" do
+        config.host_vars = {
+          "machine1" => "http_port=80 maxRequestsPerChild=808"
+        }
+        expect(Vagrant::Util::Subprocess).to receive(:execute).with { |*args|
+          inventory_content = File.read(generated_inventory_file)
+          expect(inventory_content).to match("^" + Regexp.quote(machine.name) + ".+http_port=80 maxRequestsPerChild=808")
+        }
+      end
     end
 
     describe "with groups option" do