diff --git a/ax/core/experiment.py b/ax/core/experiment.py
index 25b522fbc6d..a6f5f6afda8 100644
--- a/ax/core/experiment.py
+++ b/ax/core/experiment.py
@@ -1535,6 +1535,7 @@ def attach_trial(
         ttl_seconds: int | None = None,
         run_metadata: dict[str, Any] | None = None,
         optimize_for_power: bool = False,
+        raise_parameter_error: bool = True,
     ) -> tuple[dict[str, TParameterization], int]:
         """Attach a new trial with the given parameterization to the experiment.
 
@@ -1552,6 +1553,9 @@ def attach_trial(
                 trial such that the experiment's power to detect effects of
                 certain size is as high as possible. Refer to documentation of
                 `BatchTrial.set_status_quo_and_optimize_power` for more detail.
+            raise_parameter_error: If True, raise an error if validating membership
+                of the parameterization in the search space fails. If False, do not 
+                raise an error.
 
         Returns:
             Tuple of arm name to parameterization dict, and trial index from
@@ -1564,7 +1568,9 @@ def attach_trial(
 
         # Validate search space membership for all parameterizations
         for parameterization in parameterizations:
-            self.search_space.validate_membership(parameters=parameterization)
+            self.search_space.validate_membership(
+                parameters=parameterization, raise_error=raise_parameter_error
+            )
 
         # Validate number of arm names if any arm names are provided.
         named_arms = False
diff --git a/ax/core/search_space.py b/ax/core/search_space.py
index b75cf380596..2f1824db704 100644
--- a/ax/core/search_space.py
+++ b/ax/core/search_space.py
@@ -378,8 +378,17 @@ def _validate_parameter_constraints(
                             f"`{parameter_name}` does not exist in search space."
                         )
 
-    def validate_membership(self, parameters: TParameterization) -> None:
-        self.check_membership(parameterization=parameters, raise_error=True)
+    def validate_membership(
+        self, parameters: TParameterization, raise_error: bool = True
+    ) -> None:
+        """Validates if a parameterization belongs in the search space.
+        
+        Args:
+            raise_error: If True, raise an error if validating membership
+                of the parameterization in the search space fails. If False, do not 
+                raise an error.
+        """
+        self.check_membership(parameterization=parameters, raise_error=raise_error)
         # `check_membership` uses int and float interchangeably, which we don't
         # want here.
         for p_name, parameter in self.parameters.items():
diff --git a/ax/service/ax_client.py b/ax/service/ax_client.py
index 01a9af29c62..b7a63b0cb11 100644
--- a/ax/service/ax_client.py
+++ b/ax/service/ax_client.py
@@ -881,6 +881,7 @@ def attach_trial(
         ttl_seconds: int | None = None,
         run_metadata: dict[str, Any] | None = None,
         arm_name: str | None = None,
+        raise_parameter_error: bool = True,
     ) -> tuple[TParameterization, int]:
         """Attach a new trial with the given parameterization to the experiment.
 
@@ -889,6 +890,9 @@ def attach_trial(
             ttl_seconds: If specified, will consider the trial failed after this
                 many seconds. Used to detect dead trials that were not marked
                 failed properly.
+            raise_parameter_error: If True, raise an error if validating membership
+                of the parameterization in the search space fails. If False, do not 
+                raise an error.
 
         Returns:
             Tuple of parameterization and trial index from newly created trial.
@@ -899,6 +903,7 @@ def attach_trial(
             arm_names=[arm_name] if arm_name else None,
             ttl_seconds=ttl_seconds,
             run_metadata=run_metadata,
+            raise_parameter_error=raise_parameter_error,
         )
         self._save_or_update_trial_in_db_if_possible(
             experiment=self.experiment,
diff --git a/ax/service/tests/test_ax_client.py b/ax/service/tests/test_ax_client.py
index 7988563b6b8..26c30bdd8ce 100644
--- a/ax/service/tests/test_ax_client.py
+++ b/ax/service/tests/test_ax_client.py
@@ -1941,6 +1941,39 @@ def test_attach_trial_and_get_trial_parameters(self) -> None:
         with self.assertRaisesRegex(UnsupportedError, ".* is of type"):
             ax_client.attach_trial({"x": 1, "y": 2})
 
+    def test_attach_trial_invalid_parameters(self) -> None:
+        ax_client = AxClient()
+        ax_client.create_experiment(
+            parameters=[
+                {"name": "x", "type": "range", "bounds": [-5.0, 10.0]},
+                {"name": "y", "type": "range", "bounds": [0.0, 15.0]},
+            ],
+        )
+        # Test parameter outside bounds fails by default
+        with self.assertRaisesRegex(
+            ValueError,
+            "20\\.0 is not a valid value for parameter RangeParameter\\(name='x'",
+        ):
+            ax_client.attach_trial(parameters={"x": 20.0, "y": 1.0})
+
+        # Test parameter outside bounds fails with raise_parameter_error=True
+        with self.assertRaisesRegex(
+            ValueError,
+            "20\\.0 is not a valid value for parameter RangeParameter\\(name='x'",
+        ):
+            ax_client.attach_trial(
+                parameters={"x": 20.0, "y": 1.0}, raise_parameter_error=True
+            )
+
+        # Test parameter outside bounds succeeds with raise_parameter_error=False
+        _, idx = ax_client.attach_trial(
+            parameters={"x": 20.0, "y": 1.0}, raise_parameter_error=False
+        )
+        ax_client.complete_trial(trial_index=idx, raw_data=5)
+        self.assertEqual(
+            ax_client.get_trial_parameters(trial_index=idx), {"x": 20.0, "y": 1.0}
+        )
+
     def test_attach_trial_ttl_seconds(self) -> None:
         ax_client = AxClient()
         ax_client.create_experiment(