diff --git a/awx/api/serializers.py b/awx/api/serializers.py
index 0bb29b5408..b092d6cf7e 100644
--- a/awx/api/serializers.py
+++ b/awx/api/serializers.py
@@ -121,6 +121,8 @@ class ChoiceField(fields.ChoiceField):
     def metadata(self):
         metadata = super(ChoiceField, self).metadata()
         metadata['choices'] = self.choices or []
+        if not self.choices:
+            metadata.pop('default', None)
         return metadata
 
 # Monkeypatch REST framework to replace default ChoiceField used by
@@ -1603,6 +1605,7 @@ class JobRelaunchSerializer(JobSerializer):
 class AdHocCommandSerializer(UnifiedJobSerializer):
 
     name = serializers.CharField(source='name', read_only=True)
+    module_name = ChoiceField(source='module_name', label='module name', required=bool(not AdHocCommand.MODULE_NAME_DEFAULT), choices=AdHocCommand.MODULE_NAME_CHOICES, default=AdHocCommand.MODULE_NAME_DEFAULT)
 
     class Meta:
         model = AdHocCommand
diff --git a/awx/main/models/ad_hoc_commands.py b/awx/main/models/ad_hoc_commands.py
index ffeb90522c..1a48bbffcb 100644
--- a/awx/main/models/ad_hoc_commands.py
+++ b/awx/main/models/ad_hoc_commands.py
@@ -30,6 +30,7 @@ __all__ = ['AdHocCommand', 'AdHocCommandEvent']
 class AdHocCommand(UnifiedJob):
 
     MODULE_NAME_CHOICES = [(x,x) for x in settings.AD_HOC_COMMANDS]
+    MODULE_NAME_DEFAULT = 'command' if 'command' in settings.AD_HOC_COMMANDS else None
 
     class Meta(object):
         app_label = 'main'
@@ -59,9 +60,9 @@ class AdHocCommand(UnifiedJob):
     )
     module_name = models.CharField(
         max_length=1024,
-        default='command',
+        default=MODULE_NAME_DEFAULT,
         choices=MODULE_NAME_CHOICES,
-        blank=True, # If blank, defaults to 'command'.
+        blank=bool(MODULE_NAME_DEFAULT),
     )
     module_args = models.TextField(
         blank=True,