diff --git a/Makefile b/Makefile
index 3d43bb8..0f13b18 100644
--- a/Makefile
+++ b/Makefile
@@ -62,8 +62,8 @@ generate: \
 	src/General/Transforms/HasContextTransforms.php \
 	src/Numbers/CurrencyData.php \
 	src/Supplemental/Territory/TerritoryData.php \
-	src/Units/SequenceCompanion.php \
-	src/Units/UnitsCompanion.php
+	src/Supplemental/Units/SequenceCompanion.php \
+	src/Supplemental/Units/UnitsCompanion.php
 
 src/Core/LocaleData.php: generator/src/Command/GenerateLocaleData.php
 	$(GENERATE) $@
@@ -77,8 +77,8 @@ src/Numbers/CurrencyData.php: generator/src/Command/GenerateCurrencyData.php
 src/Supplemental/Territory/TerritoryData.php: generator/src/Command/GenerateTerritoryData.php
 	$(GENERATE) $@
 
-src/Units/SequenceCompanion.php: generator/src/Command/GenerateSequenceCompanion.php
+src/Supplemental/Units/SequenceCompanion.php: generator/src/Command/GenerateSequenceCompanion.php
 	$(GENERATE) $@
 
-src/Units/UnitsCompanion.php: generator/src/Command/GenerateUnitsCompanion.php
+src/Supplemental/Units/UnitsCompanion.php: generator/src/Command/GenerateUnitsCompanion.php
 	$(GENERATE) $@
diff --git a/generator/src/Command/GenerateSequenceCompanion.php b/generator/src/Command/GenerateSequenceCompanion.php
index 12a687b..2c2b347 100644
--- a/generator/src/Command/GenerateSequenceCompanion.php
+++ b/generator/src/Command/GenerateSequenceCompanion.php
@@ -11,7 +11,7 @@
 #[AsCommand(self::GENERATED_FILE)]
 final class GenerateSequenceCompanion extends Command
 {
-    private const GENERATED_FILE = 'src/Units/SequenceCompanion.php';
+    private const GENERATED_FILE = 'src/Supplemental/Units/SequenceCompanion.php';
 
     public function __construct(
         private readonly Repository $repository
@@ -69,7 +69,7 @@ private function render(
          * {@see \\$class}
          */
 
-        namespace ICanBoogie\CLDR\Units;
+        namespace ICanBoogie\CLDR\Supplemental\Units;
 
         /**
          * @internal
diff --git a/generator/src/Command/GenerateUnitsCompanion.php b/generator/src/Command/GenerateUnitsCompanion.php
index 4780f82..dbd696e 100644
--- a/generator/src/Command/GenerateUnitsCompanion.php
+++ b/generator/src/Command/GenerateUnitsCompanion.php
@@ -11,7 +11,7 @@
 #[AsCommand(self::GENERATED_FILE)]
 final class GenerateUnitsCompanion extends Command
 {
-    private const GENERATED_FILE = 'src/Units/UnitsCompanion.php';
+    private const GENERATED_FILE = 'src/Supplemental/Units/UnitsCompanion.php';
 
     public function __construct(
         private readonly Repository $repository
@@ -72,7 +72,7 @@ private function render(
          * {@see \\$class}
          */
 
-        namespace ICanBoogie\CLDR\Units;
+        namespace ICanBoogie\CLDR\Supplemental\Units;
 
         /**
          * @internal
diff --git a/src/Core/Locale.php b/src/Core/Locale.php
index ba80fe8..7469903 100644
--- a/src/Core/Locale.php
+++ b/src/Core/Locale.php
@@ -16,7 +16,7 @@
 use ICanBoogie\CLDR\Numbers\NumberFormatterLocalized;
 use ICanBoogie\CLDR\Numbers\Numbers;
 use ICanBoogie\CLDR\Repository;
-use ICanBoogie\CLDR\Units\Units;
+use ICanBoogie\CLDR\Supplemental\Units\Units;
 use ICanBoogie\CLDR\Warmable;
 use WeakMap;
 
diff --git a/src/Units/NumberPerUnit.php b/src/Supplemental/Units/NumberPerUnit.php
similarity index 96%
rename from src/Units/NumberPerUnit.php
rename to src/Supplemental/Units/NumberPerUnit.php
index b9286a2..22a3fa7 100644
--- a/src/Units/NumberPerUnit.php
+++ b/src/Supplemental/Units/NumberPerUnit.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace ICanBoogie\CLDR\Units;
+namespace ICanBoogie\CLDR\Supplemental\Units;
 
 use ICanBoogie\Accessor\AccessorTrait;
 
diff --git a/src/Units/NumberWithUnit.php b/src/Supplemental/Units/NumberWithUnit.php
similarity index 96%
rename from src/Units/NumberWithUnit.php
rename to src/Supplemental/Units/NumberWithUnit.php
index f1a607b..e0f8de3 100644
--- a/src/Units/NumberWithUnit.php
+++ b/src/Supplemental/Units/NumberWithUnit.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace ICanBoogie\CLDR\Units;
+namespace ICanBoogie\CLDR\Supplemental\Units;
 
 use ICanBoogie\Accessor\AccessorTrait;
 
diff --git a/src/Units/Sequence.php b/src/Supplemental/Units/Sequence.php
similarity index 96%
rename from src/Units/Sequence.php
rename to src/Supplemental/Units/Sequence.php
index 9b49c32..104f7ad 100644
--- a/src/Units/Sequence.php
+++ b/src/Supplemental/Units/Sequence.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace ICanBoogie\CLDR\Units;
+namespace ICanBoogie\CLDR\Supplemental\Units;
 
 use ICanBoogie\Accessor\AccessorTrait;
 
diff --git a/src/Units/SequenceCompanion.php b/src/Supplemental/Units/SequenceCompanion.php
similarity index 99%
rename from src/Units/SequenceCompanion.php
rename to src/Supplemental/Units/SequenceCompanion.php
index 4fc5b55..f528106 100644
--- a/src/Units/SequenceCompanion.php
+++ b/src/Supplemental/Units/SequenceCompanion.php
@@ -6,7 +6,7 @@
  * {@see \ICanBoogie\CLDR\Generator\Command\GenerateSequenceCompanion}
  */
 
-namespace ICanBoogie\CLDR\Units;
+namespace ICanBoogie\CLDR\Supplemental\Units;
 
 /**
  * @internal
diff --git a/src/Units/Unit.php b/src/Supplemental/Units/Unit.php
similarity index 96%
rename from src/Units/Unit.php
rename to src/Supplemental/Units/Unit.php
index 6d82fb4..60d2fc8 100644
--- a/src/Units/Unit.php
+++ b/src/Supplemental/Units/Unit.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace ICanBoogie\CLDR\Units;
+namespace ICanBoogie\CLDR\Supplemental\Units;
 
 use ICanBoogie\Accessor\AccessorTrait;
 
diff --git a/src/Units/UnitLength.php b/src/Supplemental/Units/UnitLength.php
similarity index 71%
rename from src/Units/UnitLength.php
rename to src/Supplemental/Units/UnitLength.php
index 6f692b0..6007339 100644
--- a/src/Units/UnitLength.php
+++ b/src/Supplemental/Units/UnitLength.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace ICanBoogie\CLDR\Units;
+namespace ICanBoogie\CLDR\Supplemental\Units;
 
 enum UnitLength: string
 {
diff --git a/src/Units/Units.php b/src/Supplemental/Units/Units.php
similarity index 99%
rename from src/Units/Units.php
rename to src/Supplemental/Units/Units.php
index 21ec1ab..7df8c72 100644
--- a/src/Units/Units.php
+++ b/src/Supplemental/Units/Units.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace ICanBoogie\CLDR\Units;
+namespace ICanBoogie\CLDR\Supplemental\Units;
 
 use ICanBoogie\CLDR\Core\Locale;
 use ICanBoogie\CLDR\General\Lists\ListType;
diff --git a/src/Units/UnitsCompanion.php b/src/Supplemental/Units/UnitsCompanion.php
similarity index 99%
rename from src/Units/UnitsCompanion.php
rename to src/Supplemental/Units/UnitsCompanion.php
index 38644d8..7c1c3ff 100644
--- a/src/Units/UnitsCompanion.php
+++ b/src/Supplemental/Units/UnitsCompanion.php
@@ -6,7 +6,7 @@
  * {@see \ICanBoogie\CLDR\Generator\Command\GenerateUnitsCompanion}
  */
 
-namespace ICanBoogie\CLDR\Units;
+namespace ICanBoogie\CLDR\Supplemental\Units;
 
 /**
  * @internal
diff --git a/tests/Core/LocaleTest.php b/tests/Core/LocaleTest.php
index d2ae20c..2a4c5a5 100644
--- a/tests/Core/LocaleTest.php
+++ b/tests/Core/LocaleTest.php
@@ -11,7 +11,7 @@
 use ICanBoogie\CLDR\Numbers\NumberFormatterLocalized;
 use ICanBoogie\CLDR\Numbers\Numbers;
 use ICanBoogie\CLDR\Repository;
-use ICanBoogie\CLDR\Units\Units;
+use ICanBoogie\CLDR\Supplemental\Units\Units;
 use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\TestCase;
 use Test\ICanBoogie\CLDR\StringHelpers;
diff --git a/tests/General/UnitsTest.php b/tests/General/UnitsTest.php
index 4138682..a216dde 100644
--- a/tests/General/UnitsTest.php
+++ b/tests/General/UnitsTest.php
@@ -3,8 +3,8 @@
 namespace Test\ICanBoogie\CLDR\General;
 
 use ICanBoogie\CLDR\Spaces;
-use ICanBoogie\CLDR\Units\UnitLength;
-use ICanBoogie\CLDR\Units\Units;
+use ICanBoogie\CLDR\Supplemental\Units\UnitLength;
+use ICanBoogie\CLDR\Supplemental\Units\Units;
 use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\TestCase;
 use Test\ICanBoogie\CLDR\StringHelpers;
diff --git a/tests/Units/NumberPerUnitTest.php b/tests/Supplemental/Units/NumberPerUnitTest.php
similarity index 91%
rename from tests/Units/NumberPerUnitTest.php
rename to tests/Supplemental/Units/NumberPerUnitTest.php
index d60e820..5870277 100644
--- a/tests/Units/NumberPerUnitTest.php
+++ b/tests/Supplemental/Units/NumberPerUnitTest.php
@@ -1,10 +1,10 @@
 <?php
 
-namespace Test\ICanBoogie\CLDR\Units;
+namespace Test\ICanBoogie\CLDR\Supplemental\Units;
 
-use ICanBoogie\CLDR\Units\NumberPerUnit;
-use ICanBoogie\CLDR\Units\UnitLength;
-use ICanBoogie\CLDR\Units\Units;
+use ICanBoogie\CLDR\Supplemental\Units\NumberPerUnit;
+use ICanBoogie\CLDR\Supplemental\Units\UnitLength;
+use ICanBoogie\CLDR\Supplemental\Units\Units;
 use PHPUnit\Framework\TestCase;
 use Test\ICanBoogie\CLDR\StringHelpers;
 
diff --git a/tests/Units/NumberWithUnitTest.php b/tests/Supplemental/Units/NumberWithUnitTest.php
similarity index 94%
rename from tests/Units/NumberWithUnitTest.php
rename to tests/Supplemental/Units/NumberWithUnitTest.php
index 8467c44..beccba7 100644
--- a/tests/Units/NumberWithUnitTest.php
+++ b/tests/Supplemental/Units/NumberWithUnitTest.php
@@ -1,10 +1,10 @@
 <?php
 
-namespace Test\ICanBoogie\CLDR\Units;
+namespace Test\ICanBoogie\CLDR\Supplemental\Units;
 
-use ICanBoogie\CLDR\Units\NumberWithUnit;
-use ICanBoogie\CLDR\Units\UnitLength;
-use ICanBoogie\CLDR\Units\Units;
+use ICanBoogie\CLDR\Supplemental\Units\NumberWithUnit;
+use ICanBoogie\CLDR\Supplemental\Units\UnitLength;
+use ICanBoogie\CLDR\Supplemental\Units\Units;
 use PHPUnit\Framework\TestCase;
 use Test\ICanBoogie\CLDR\StringHelpers;
 
diff --git a/tests/Units/SequenceTest.php b/tests/Supplemental/Units/SequenceTest.php
similarity index 88%
rename from tests/Units/SequenceTest.php
rename to tests/Supplemental/Units/SequenceTest.php
index 58147eb..2205727 100644
--- a/tests/Units/SequenceTest.php
+++ b/tests/Supplemental/Units/SequenceTest.php
@@ -1,10 +1,10 @@
 <?php
 
-namespace Test\ICanBoogie\CLDR\Units;
+namespace Test\ICanBoogie\CLDR\Supplemental\Units;
 
-use ICanBoogie\CLDR\Units\Sequence;
-use ICanBoogie\CLDR\Units\UnitLength;
-use ICanBoogie\CLDR\Units\Units;
+use ICanBoogie\CLDR\Supplemental\Units\Sequence;
+use ICanBoogie\CLDR\Supplemental\Units\UnitLength;
+use ICanBoogie\CLDR\Supplemental\Units\Units;
 use PHPUnit\Framework\TestCase;
 
 final class SequenceTest extends TestCase
diff --git a/tests/Units/UnitTest.php b/tests/Supplemental/Units/UnitTest.php
similarity index 88%
rename from tests/Units/UnitTest.php
rename to tests/Supplemental/Units/UnitTest.php
index 342a9ea..23510c0 100644
--- a/tests/Units/UnitTest.php
+++ b/tests/Supplemental/Units/UnitTest.php
@@ -1,10 +1,10 @@
 <?php
 
-namespace Test\ICanBoogie\CLDR\Units;
+namespace Test\ICanBoogie\CLDR\Supplemental\Units;
 
-use ICanBoogie\CLDR\Units\Unit;
-use ICanBoogie\CLDR\Units\UnitLength;
-use ICanBoogie\CLDR\Units\Units;
+use ICanBoogie\CLDR\Supplemental\Units\Unit;
+use ICanBoogie\CLDR\Supplemental\Units\UnitLength;
+use ICanBoogie\CLDR\Supplemental\Units\Units;
 use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\TestCase;