diff --git a/src/lib/default-config.ts b/src/lib/default-config.ts
index 438e0ad..68fb031 100644
--- a/src/lib/default-config.ts
+++ b/src/lib/default-config.ts
@@ -1658,6 +1658,11 @@ export const getDefaultConfig = () => {
              * @see https://tailwindcss.com/docs/just-in-time-mode#caret-color-utilities
              */
             'caret-color': [{ caret: [colors] }],
+            /**
+             * Field Sizing
+             * @see https://tailwindcss.com/docs/field-sizing
+             */
+            'field-sizing': [{ 'field-sizing': ['fixed', 'content'] }],
             /**
              * Pointer Events
              * @see https://tailwindcss.com/docs/pointer-events
diff --git a/src/lib/types.ts b/src/lib/types.ts
index efc2db6..c58346b 100644
--- a/src/lib/types.ts
+++ b/src/lib/types.ts
@@ -285,6 +285,7 @@ export type DefaultClassGroupIds =
     | 'duration'
     | 'ease'
     | 'end'
+    | 'field-sizing'
     | 'fill'
     | 'filter'
     | 'flex-direction'
@@ -323,8 +324,8 @@ export type DefaultClassGroupIds =
     | 'indent'
     | 'inset-ring-color'
     | 'inset-ring-w'
-    | 'inset-shadow'
     | 'inset-shadow-color'
+    | 'inset-shadow'
     | 'inset-x'
     | 'inset-y'
     | 'inset'
diff --git a/tests/class-map.test.ts b/tests/class-map.test.ts
index 24e59d1..19f5744 100644
--- a/tests/class-map.test.ts
+++ b/tests/class-map.test.ts
@@ -109,6 +109,7 @@ test('class map has correct class groups at first part', () => {
         duration: ['duration'],
         ease: ['ease'],
         end: ['end'],
+        field: ['field-sizing'],
         fill: ['fill'],
         filter: ['filter'],
         fixed: ['position'],
diff --git a/tests/tailwind-css-versions.test.ts b/tests/tailwind-css-versions.test.ts
index add4964..63a3449 100644
--- a/tests/tailwind-css-versions.test.ts
+++ b/tests/tailwind-css-versions.test.ts
@@ -74,6 +74,7 @@ test('supports Tailwind CSS v4.0 features', () => {
     expect(twMerge('ring-4 ring-orange inset-ring inset-ring-3 inset-ring-blue')).toBe(
         'ring-4 ring-orange inset-ring-3 inset-ring-blue',
     )
+    expect(twMerge('field-sizing-content field-sizing-fixed')).toBe('field-sizing-fixed')
 
     // TODO: Remove proto
     expect(twMerge('')).toBe('')