diff --git a/src/FileExtension.php b/src/FileExtension.php
index 2a5854ce..ccedccc5 100644
--- a/src/FileExtension.php
+++ b/src/FileExtension.php
@@ -17,6 +17,7 @@ enum FileExtension: string
     case TIFF = 'tiff';
     case JP2 = 'jp2';
     case J2K = 'j2k';
+    case JP2K = 'jp2k';
     case JPF = 'jpf';
     case JPM = 'jpm';
     case JPG2 = 'jpg2';
@@ -44,6 +45,7 @@ public function format(): Format
             self::TIF,
             self::TIFF => Format::TIFF,
             self::JP2,
+            self::JP2K,
             self::J2K,
             self::JPF,
             self::JPM,
diff --git a/tests/Unit/FileExtensionTest.php b/tests/Unit/FileExtensionTest.php
index 69051264..b7d3fd08 100644
--- a/tests/Unit/FileExtensionTest.php
+++ b/tests/Unit/FileExtensionTest.php
@@ -76,6 +76,9 @@ public function testFormatJpeg2000(): void
 
         $ext = FileExtension::JPG2;
         $this->assertEquals(Format::JP2, $ext->format());
+
+        $ext = FileExtension::JP2K;
+        $this->assertEquals(Format::JP2, $ext->format());
     }
 
     public function testFormatHeic(): void
diff --git a/tests/Unit/FormatTest.php b/tests/Unit/FormatTest.php
index 4697f5d2..96b87d19 100644
--- a/tests/Unit/FormatTest.php
+++ b/tests/Unit/FormatTest.php
@@ -271,7 +271,7 @@ public function testFileExtensionsJp2(): void
         $format = Format::JP2;
         $extensions = $format->fileExtensions();
         $this->assertIsArray($extensions);
-        $this->assertCount(8, $extensions);
+        $this->assertCount(9, $extensions);
 
         $this->assertEquals(FileExtension::JP2, $format->fileExtension());
     }
diff --git a/tests/Unit/MediaTypeTest.php b/tests/Unit/MediaTypeTest.php
index 56aceba4..db00c5ff 100644
--- a/tests/Unit/MediaTypeTest.php
+++ b/tests/Unit/MediaTypeTest.php
@@ -143,9 +143,9 @@ public static function fileExtensionsDataProvider(): Generator
         yield [MediaType::IMAGE_X_WIN_BITMAP, 1, FileExtension::BMP];
         yield [MediaType::IMAGE_X_XBITMAP, 1, FileExtension::BMP];
         yield [MediaType::IMAGE_TIFF, 2, FileExtension::TIF];
-        yield [MediaType::IMAGE_JP2, 8, FileExtension::JP2];
-        yield [MediaType::IMAGE_JPX, 8, FileExtension::JP2];
-        yield [MediaType::IMAGE_JPM, 8, FileExtension::JP2];
+        yield [MediaType::IMAGE_JP2, 9, FileExtension::JP2];
+        yield [MediaType::IMAGE_JPX, 9, FileExtension::JP2];
+        yield [MediaType::IMAGE_JPM, 9, FileExtension::JP2];
         yield [MediaType::IMAGE_HEIC, 2, FileExtension::HEIC];
         yield [MediaType::IMAGE_X_HEIC, 2, FileExtension::HEIC];
         yield [MediaType::IMAGE_HEIF, 2, FileExtension::HEIC];