diff --git a/ax/service/utils/instantiation.py b/ax/service/utils/instantiation.py
index 791781bf983..824eef17e7b 100644
--- a/ax/service/utils/instantiation.py
+++ b/ax/service/utils/instantiation.py
@@ -153,6 +153,12 @@ def _make_metric(
         for_opt_config: bool = False,
         metric_definitions: Optional[Dict[str, Dict[str, Any]]] = None,
     ) -> Metric:
+        if " " in name:
+            raise ValueError(
+                "Metric names cannot contain spaces when used with AxClient. Got "
+                f"{name}."
+            )
+
         return metric_class(
             name=name,
             lower_is_better=lower_is_better,
@@ -314,6 +320,12 @@ def parameter_from_json(
                 "'bool' or 'str'."
             )
 
+        if " " in name:
+            raise ValueError(
+                "Parameter names cannot contain spaces when used with AxClient. Got "
+                f"{name}."
+            )
+
         if parameter_class == "range":
             return cls._make_range_param(
                 name=name,