diff --git a/doc/changelog.md b/doc/changelog.md
index 23bbed5c6..26388a05e 100644
--- a/doc/changelog.md
+++ b/doc/changelog.md
@@ -15,6 +15,8 @@ To be released at some future point in time
 
 Description
 
+- Allow specifying Model and Ensemble parameters with 
+  number-like types (e.g. numpy types)
 - Pin watchdog to 4.x
 - Update codecov to 4.5.0
 - Remove build of Redis from setup.py
@@ -31,6 +33,11 @@ Description
 
 Detailed Notes
 
+- The serializer would fail if a parameter for a Model or Ensemble 
+  was specified as a numpy dtype. The constructors for these 
+  methods now validate that the input is number-like and convert 
+  them to strings
+  ([SmartSim-PR676](https://github.com/CrayLabs/SmartSim/pull/676))
 - Pin watchdog to 4.x because v5 introduces new types and requires
   updates to the type-checking
   ([SmartSim-PR690](https://github.com/CrayLabs/SmartSim/pull/690))
diff --git a/smartsim/entity/model.py b/smartsim/entity/model.py
index 3f78e042c..a11a594fc 100644
--- a/smartsim/entity/model.py
+++ b/smartsim/entity/model.py
@@ -27,6 +27,7 @@
 from __future__ import annotations
 
 import itertools
+import numbers
 import re
 import sys
 import typing as t
@@ -46,6 +47,25 @@
 logger = get_logger(__name__)
 
 
+def _parse_model_parameters(params_dict: t.Dict[str, t.Any]) -> t.Dict[str, str]:
+    """Convert the values in a params dict to strings
+    :raises TypeError: if params are of the wrong type
+    :return: param dictionary with values and keys cast as strings
+    """
+    param_names: t.List[str] = []
+    parameters: t.List[str] = []
+    for name, val in params_dict.items():
+        param_names.append(name)
+        if isinstance(val, (str, numbers.Number)):
+            parameters.append(str(val))
+        else:
+            raise TypeError(
+                "Incorrect type for model parameters\n"
+                + "Must be numeric value or string."
+            )
+    return dict(zip(param_names, parameters))
+
+
 class Model(SmartSimEntity):
     def __init__(
         self,
@@ -70,7 +90,7 @@ def __init__(
                                model as a batch job
         """
         super().__init__(name, str(path), run_settings)
-        self.params = params
+        self.params = _parse_model_parameters(params)
         self.params_as_args = params_as_args
         self.incoming_entities: t.List[SmartSimEntity] = []
         self._key_prefixing_enabled = False
diff --git a/tests/test_model.py b/tests/test_model.py
index 64a68b299..152ce2058 100644
--- a/tests/test_model.py
+++ b/tests/test_model.py
@@ -26,12 +26,14 @@
 
 from uuid import uuid4
 
+import numpy as np
 import pytest
 
 from smartsim import Experiment
 from smartsim._core.control.manifest import LaunchedManifestBuilder
 from smartsim._core.launcher.step import SbatchStep, SrunStep
 from smartsim.entity import Ensemble, Model
+from smartsim.entity.model import _parse_model_parameters
 from smartsim.error import EntityExistsError, SSUnsupportedError
 from smartsim.settings import RunSettings, SbatchSettings, SrunSettings
 from smartsim.settings.mpiSettings import _BaseMPISettings
@@ -176,3 +178,16 @@ def test_models_batch_settings_are_ignored_in_ensemble(
     step_cmd = step.step_cmds[0]
     assert any("srun" in tok for tok in step_cmd)  # call the model using run settings
     assert not any("sbatch" in tok for tok in step_cmd)  # no sbatch in sbatch
+
+
+@pytest.mark.parametrize("dtype", [int, np.float32, str])
+def test_good_model_params(dtype):
+    print(dtype(0.6))
+    params = {"foo": dtype(0.6)}
+    assert all(isinstance(val, str) for val in _parse_model_parameters(params).values())
+
+
+@pytest.mark.parametrize("bad_val", [["eggs"], {"n": 5}, object])
+def test_bad_model_params(bad_val):
+    with pytest.raises(TypeError):
+        _parse_model_parameters({"foo": bad_val})
diff --git a/tests/test_preview.py b/tests/test_preview.py
index 3c7bed6fe..a18d10728 100644
--- a/tests/test_preview.py
+++ b/tests/test_preview.py
@@ -357,7 +357,7 @@ def test_model_preview_properties(test_dir, wlmutils):
     assert hw_rs == hello_world_model.run_settings.exe_args[0]
     assert None == hello_world_model.batch_settings
     assert "port" in list(hello_world_model.params.items())[0]
-    assert hw_port in list(hello_world_model.params.items())[0]
+    assert str(hw_port) in list(hello_world_model.params.items())[0]
     assert "password" in list(hello_world_model.params.items())[1]
     assert hw_password in list(hello_world_model.params.items())[1]