diff --git a/poetry.lock b/poetry.lock
index f8d21e5b..50e2bf8b 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -1172,6 +1172,24 @@ python-dateutil = ">=2.7"
 [package.extras]
 dev = ["meson-python (>=0.13.1,<0.17.0)", "pybind11 (>=2.13.2,!=2.13.3)", "setuptools (>=64)", "setuptools_scm (>=7)"]
 
+[[package]]
+name = "mpmath"
+version = "1.3.0"
+description = "Python library for arbitrary-precision floating-point arithmetic"
+optional = false
+python-versions = "*"
+groups = ["main"]
+files = [
+    {file = "mpmath-1.3.0-py3-none-any.whl", hash = "sha256:a0b2b9fe80bbcd81a6647ff13108738cfb482d481d826cc0e02f5b35e5c88d2c"},
+    {file = "mpmath-1.3.0.tar.gz", hash = "sha256:7a28eb2a9774d00c7bc92411c19a89209d5da7c4c9a9e227be8330a23a25b91f"},
+]
+
+[package.extras]
+develop = ["codecov", "pycodestyle", "pytest (>=4.6)", "pytest-cov", "wheel"]
+docs = ["sphinx"]
+gmpy = ["gmpy2 (>=2.1.0a4) ; platform_python_implementation != \"PyPy\""]
+tests = ["pytest (>=4.6)"]
+
 [[package]]
 name = "msgpack"
 version = "1.1.2"
@@ -2317,6 +2335,24 @@ files = [
     {file = "smmap-5.0.3.tar.gz", hash = "sha256:4d9debb8b99007ae47165abc08670bd74cb74b5227dda7f643eccc4e9eb5642c"},
 ]
 
+[[package]]
+name = "sympy"
+version = "1.14.0"
+description = "Computer algebra system (CAS) in Python"
+optional = false
+python-versions = ">=3.9"
+groups = ["main"]
+files = [
+    {file = "sympy-1.14.0-py3-none-any.whl", hash = "sha256:e091cc3e99d2141a0ba2847328f5479b05d94a6635cb96148ccb3f34671bd8f5"},
+    {file = "sympy-1.14.0.tar.gz", hash = "sha256:d3d3fe8df1e5a0b42f0e7bdf50541697dbe7d23746e894990c030e2b05e72517"},
+]
+
+[package.dependencies]
+mpmath = ">=1.1.0,<1.4"
+
+[package.extras]
+dev = ["hypothesis (>=6.70.0)", "pytest (>=7.1.0)"]
+
 [[package]]
 name = "tabulate"
 version = "0.9.0"
@@ -2488,6 +2524,23 @@ files = [
     {file = "tzdata-2026.1.tar.gz", hash = "sha256:67658a1903c75917309e753fdc349ac0efd8c27db7a0cb406a25be4840f87f98"},
 ]
 
+[[package]]
+name = "unyt"
+version = "3.1.0"
+description = "A package for handling numpy arrays with units"
+optional = false
+python-versions = ">=3.10"
+groups = ["main"]
+files = [
+    {file = "unyt-3.1.0-py3-none-any.whl", hash = "sha256:6ff9efe694a1c13f5b07ccb4c6b30a0e282d5e4989947f0ef5aadf4ad7be3f69"},
+    {file = "unyt-3.1.0.tar.gz", hash = "sha256:771582a87f1e521c9b62f7ca269b1965c0f77b479f7a063a51e8cef8b4cae51d"},
+]
+
+[package.dependencies]
+numpy = ">=1.21.3,<3.0"
+packaging = ">=20.9"
+sympy = ">=1.9.0"
+
 [[package]]
 name = "urllib3"
 version = "2.6.3"
@@ -2512,4 +2565,4 @@ plot = ["matplotlib", "plotly"]
 [metadata]
 lock-version = "2.1"
 python-versions = ">=3.10,<3.15"
-content-hash = "ac08fbf5d9a233743b7f3e4035c700c30db4a9b73efbf502047082cf575210e8"
+content-hash = "56c850f5ad4d927f7b6bb852189b4a557550484b13513811d3d5efe1885f8a24"
diff --git a/pyproject.toml b/pyproject.toml
index 54041d85..7ecb6164 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -56,6 +56,7 @@ dependencies = [
   "pyyaml (>=6.0.2,<7.0.0)",
   "flatdict (==4.0.0)",
   "pytest (>=9.0.3,<10.0.0)",
+  "unyt (>=3.1.0,<4.0.0)",
 ]
 
 [project.urls]
diff --git a/simvue/run.py b/simvue/run.py
index a160fa75..60a92a8c 100644
--- a/simvue/run.py
+++ b/simvue/run.py
@@ -17,6 +17,8 @@
 import humanfriendly
 import datetime
 import os
+from unyt import unyt_quantity
+from unyt.exceptions import UnitParseError
 
 import pydantic
 import re
@@ -183,6 +185,8 @@ def __init__(
         self._executor = Executor(self)
         self._dispatcher: DispatcherBaseClass | None = None
 
+        self._meta_cache: dict[str, typing.Any] = {}
+
         self._folder: Folder | None = None
         self._term_color: bool = True
         self._grids: dict[str, str] = {}
@@ -1680,6 +1684,12 @@ def log_metrics(
             )
         ```
         """
+
+        # If there are any metric units to be uploaded do so now
+        if _units := self._meta_cache.get("metrics"):
+            self.update_metadata({"simvue": {"metrics": _units}})
+            del self._meta_cache["metrics"]
+
         # TODO: When metrics and grids are combined into a single entity
         # this can be removed. For now need to separate tensor based metrics
         # from regular
@@ -2586,3 +2596,40 @@ def log_alert(
         _alert.commit()
 
         return True
+
+    @prettify_pydantic
+    @pydantic.validate_call
+    def set_metric_units(
+        self,
+        metric_name: MetricKeyString,
+        *,
+        units: str,
+        mks_unit: str | None = None,
+        mks_conversion: float | None = None,
+    ) -> None:
+        """Define units for metrics.
+
+        Parameters
+        ----------
+        metric_name : str
+            name of metric to assign units to
+        units : str
+            unit symbol
+        label : str | None, optional
+            alternative longer name for units
+        """
+        self._meta_cache.setdefault("metrics", {})
+
+        try:
+            _unit_obj = unyt_quantity.from_string(units)
+            self._meta_cache["metrics"][metric_name] = {
+                "units": units,
+                "mks_conversion": mks_conversion or float(_unit_obj.in_mks().value),
+                "mks_units": mks_unit or f"{_unit_obj.in_mks().units}",
+            }
+        except UnitParseError:
+            self._meta_cache["metrics"][metric_name] = {
+                "units": units,
+                "mks_conversion": mks_conversion,
+                "mks_units": mks_unit,
+            }
diff --git a/tests/functional/test_run_class.py b/tests/functional/test_run_class.py
index 0057a93b..aee52d33 100644
--- a/tests/functional/test_run_class.py
+++ b/tests/functional/test_run_class.py
@@ -1724,3 +1724,18 @@ def test_no_alert_dupes_different_run(alert_type: typing.Literal["user", "events
             else:
                 MetricsRangeAlert(identifier=created_id).delete()
 
+
+@pytest.mark.run
+@pytest.mark.online
+def test_set_metric_units(create_plain_run: tuple[sv_run.Run, dict]) -> None:
+    run, _ = create_plain_run
+    run.set_metric_units("x", units="ft")
+    run.set_metric_units("y", units="m")
+    run.set_metric_units("z", units="Foobars", mks_conversion=3.542, mks_unit="m")
+    run.log_metrics({"x": 10, "y": 3, "z": 22})
+
+    _metadata = RunObject(run.id).metadata
+    assert (_metric_data := _metadata.get("simvue", {}).get("metrics"))
+    assert _metric_data["x"] == {"units": "ft", "mks_units": "m", "mks_conversion": 0.3048}
+    assert _metric_data["y"] == {"units": "m", "mks_units": "m", "mks_conversion": 1}
+    assert _metric_data["z"] == {"units": "Foobars", "mks_units": "m", "mks_conversion": 3.542}