diff --git a/homeassistant/const.py b/homeassistant/const.py
index 776b1101fc6..81e71fa4f9a 100644
--- a/homeassistant/const.py
+++ b/homeassistant/const.py
@@ -896,6 +896,7 @@ class UnitOfLength(StrEnum):
     FEET = "ft"
     YARDS = "yd"
     MILES = "mi"
+    NAUTICALMILES = "nmi"
 
 
 _DEPRECATED_LENGTH_MILLIMETERS: Final = DeprecatedConstantEnum(
diff --git a/homeassistant/util/unit_conversion.py b/homeassistant/util/unit_conversion.py
index 0f2f6464ed8..02591010b77 100644
--- a/homeassistant/util/unit_conversion.py
+++ b/homeassistant/util/unit_conversion.py
@@ -158,10 +158,12 @@ class DistanceConverter(BaseUnitConverter):
         UnitOfLength.FEET: 1 / _FOOT_TO_M,
         UnitOfLength.YARDS: 1 / _YARD_TO_M,
         UnitOfLength.MILES: 1 / _MILE_TO_M,
+        UnitOfLength.NAUTICALMILES: 1 / _NAUTICAL_MILE_TO_M,
     }
     VALID_UNITS = {
         UnitOfLength.KILOMETERS,
         UnitOfLength.MILES,
+        UnitOfLength.NAUTICALMILES,
         UnitOfLength.FEET,
         UnitOfLength.METERS,
         UnitOfLength.CENTIMETERS,
diff --git a/homeassistant/util/unit_system.py b/homeassistant/util/unit_system.py
index 02a115e10c1..e2e41614d3e 100644
--- a/homeassistant/util/unit_system.py
+++ b/homeassistant/util/unit_system.py
@@ -238,6 +238,7 @@ METRIC_SYSTEM = UnitSystem(
         ("distance", UnitOfLength.FEET): UnitOfLength.METERS,
         ("distance", UnitOfLength.INCHES): UnitOfLength.MILLIMETERS,
         ("distance", UnitOfLength.MILES): UnitOfLength.KILOMETERS,
+        ("distance", UnitOfLength.NAUTICALMILES): UnitOfLength.KILOMETERS,
         ("distance", UnitOfLength.YARDS): UnitOfLength.METERS,
         # Convert non-metric volumes of gas meters
         ("gas", UnitOfVolume.CENTUM_CUBIC_FEET): UnitOfVolume.CUBIC_METERS,
diff --git a/tests/util/test_unit_conversion.py b/tests/util/test_unit_conversion.py
index 2408914f256..7bf8f9db04a 100644
--- a/tests/util/test_unit_conversion.py
+++ b/tests/util/test_unit_conversion.py
@@ -173,6 +173,13 @@ _CONVERTED_VALUE: dict[
         (5, UnitOfLength.MILES, 8800.0, UnitOfLength.YARDS),
         (5, UnitOfLength.MILES, 26400.0008448, UnitOfLength.FEET),
         (5, UnitOfLength.MILES, 316800.171072, UnitOfLength.INCHES),
+        (5, UnitOfLength.NAUTICALMILES, 9.26, UnitOfLength.KILOMETERS),
+        (5, UnitOfLength.NAUTICALMILES, 9260.0, UnitOfLength.METERS),
+        (5, UnitOfLength.NAUTICALMILES, 926000.0, UnitOfLength.CENTIMETERS),
+        (5, UnitOfLength.NAUTICALMILES, 9260000.0, UnitOfLength.MILLIMETERS),
+        (5, UnitOfLength.NAUTICALMILES, 10126.859142607176, UnitOfLength.YARDS),
+        (5, UnitOfLength.NAUTICALMILES, 30380.57742782153, UnitOfLength.FEET),
+        (5, UnitOfLength.NAUTICALMILES, 364566.9291338583, UnitOfLength.INCHES),
         (5, UnitOfLength.YARDS, 0.004572, UnitOfLength.KILOMETERS),
         (5, UnitOfLength.YARDS, 4.572, UnitOfLength.METERS),
         (5, UnitOfLength.YARDS, 457.2, UnitOfLength.CENTIMETERS),
diff --git a/tests/util/test_unit_system.py b/tests/util/test_unit_system.py
index 316a9ead17a..6c15ae9aa23 100644
--- a/tests/util/test_unit_system.py
+++ b/tests/util/test_unit_system.py
@@ -725,6 +725,7 @@ UNCONVERTED_UNITS_US_SYSTEM = {
     SensorDeviceClass.DISTANCE: (
         UnitOfLength.FEET,
         UnitOfLength.INCHES,
+        UnitOfLength.NAUTICALMILES,
         UnitOfLength.MILES,
         UnitOfLength.YARDS,
     ),