diff --git a/homeassistant/components/number/const.py b/homeassistant/components/number/const.py
index 3f29dd04166..7330b781e75 100644
--- a/homeassistant/components/number/const.py
+++ b/homeassistant/components/number/const.py
@@ -404,7 +404,7 @@ class NumberDeviceClass(StrEnum):
     """Generic flow rate
 
     Unit of measurement: UnitOfVolumeFlowRate
-    - SI / metric: `m³/h`, `L/min`
+    - SI / metric: `m³/h`, `L/min`, `mL/s`
     - USCS / imperial: `ft³/min`, `gal/min`
     """
 
diff --git a/homeassistant/components/sensor/const.py b/homeassistant/components/sensor/const.py
index c290a627b07..87012c3631a 100644
--- a/homeassistant/components/sensor/const.py
+++ b/homeassistant/components/sensor/const.py
@@ -427,7 +427,7 @@ class SensorDeviceClass(StrEnum):
     """Generic flow rate
 
     Unit of measurement: UnitOfVolumeFlowRate
-    - SI / metric: `m³/h`, `L/min`
+    - SI / metric: `m³/h`, `L/min`, `mL/s`
     - USCS / imperial: `ft³/min`, `gal/min`
     """
 
diff --git a/homeassistant/const.py b/homeassistant/const.py
index 5a3a3f292ff..514c2154611 100644
--- a/homeassistant/const.py
+++ b/homeassistant/const.py
@@ -1166,6 +1166,7 @@ class UnitOfVolumeFlowRate(StrEnum):
     CUBIC_FEET_PER_MINUTE = "ft³/min"
     LITERS_PER_MINUTE = "L/min"
     GALLONS_PER_MINUTE = "gal/min"
+    MILLILITERS_PER_SECOND = "mL/s"
 
 
 _DEPRECATED_VOLUME_FLOW_RATE_CUBIC_METERS_PER_HOUR: Final = DeprecatedConstantEnum(
diff --git a/homeassistant/util/unit_conversion.py b/homeassistant/util/unit_conversion.py
index b700c66f248..3cffcb5768e 100644
--- a/homeassistant/util/unit_conversion.py
+++ b/homeassistant/util/unit_conversion.py
@@ -666,12 +666,15 @@ class VolumeFlowRateConverter(BaseUnitConverter):
         / (_HRS_TO_MINUTES * _L_TO_CUBIC_METER),
         UnitOfVolumeFlowRate.GALLONS_PER_MINUTE: 1
         / (_HRS_TO_MINUTES * _GALLON_TO_CUBIC_METER),
+        UnitOfVolumeFlowRate.MILLILITERS_PER_SECOND: 1
+        / (_HRS_TO_SECS * _ML_TO_CUBIC_METER),
     }
     VALID_UNITS = {
         UnitOfVolumeFlowRate.CUBIC_FEET_PER_MINUTE,
         UnitOfVolumeFlowRate.CUBIC_METERS_PER_HOUR,
         UnitOfVolumeFlowRate.LITERS_PER_MINUTE,
         UnitOfVolumeFlowRate.GALLONS_PER_MINUTE,
+        UnitOfVolumeFlowRate.MILLILITERS_PER_SECOND,
     }
 
 
diff --git a/tests/util/test_unit_conversion.py b/tests/util/test_unit_conversion.py
index 60144f81714..4d1eda3d8de 100644
--- a/tests/util/test_unit_conversion.py
+++ b/tests/util/test_unit_conversion.py
@@ -743,6 +743,18 @@ _CONVERTED_VALUE: dict[
             7.48051948,
             UnitOfVolumeFlowRate.GALLONS_PER_MINUTE,
         ),
+        (
+            9,
+            UnitOfVolumeFlowRate.CUBIC_METERS_PER_HOUR,
+            2500,
+            UnitOfVolumeFlowRate.MILLILITERS_PER_SECOND,
+        ),
+        (
+            3,
+            UnitOfVolumeFlowRate.LITERS_PER_MINUTE,
+            50,
+            UnitOfVolumeFlowRate.MILLILITERS_PER_SECOND,
+        ),
     ],
 }