diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3ad1df938f5f..1421e827fbd5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -22,6 +22,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Ensure `@keyframes` are correctly emitted when using a prefixed setup ([#16850](https://github.com/tailwindlabs/tailwindcss/pull/16850))
 - Don't swallow `@utility` declarations when `@apply` is used in nested rules ([#16940](https://github.com/tailwindlabs/tailwindcss/pull/16940))
 - Ensure `outline-hidden` behaves like `outline-none` in non-`forced-colors` mode ([#](https://github.com/tailwindlabs/tailwindcss/pull/))
+- Allow `!important` on CSS variables again ([#16873](https://github.com/tailwindlabs/tailwindcss/pull/16873))
 
 ## [4.0.9] - 2025-02-25
 
diff --git a/packages/tailwindcss/src/compile.ts b/packages/tailwindcss/src/compile.ts
index cf20ada9ec72..cd822b368cba 100644
--- a/packages/tailwindcss/src/compile.ts
+++ b/packages/tailwindcss/src/compile.ts
@@ -304,7 +304,7 @@ function applyImportant(ast: AstNode[]): void {
       continue
     }
 
-    if (node.kind === 'declaration' && !(node.property[0] === '-' && node.property[1] === '-')) {
+    if (node.kind === 'declaration') {
       node.important = true
     } else if (node.kind === 'rule' || node.kind === 'at-rule') {
       applyImportant(node.nodes)
diff --git a/packages/tailwindcss/src/important.test.ts b/packages/tailwindcss/src/important.test.ts
index 7a27fb6e6d2a..b3594219b6f4 100644
--- a/packages/tailwindcss/src/important.test.ts
+++ b/packages/tailwindcss/src/important.test.ts
@@ -110,7 +110,7 @@ test('variables in utilities should not be marked as important', async () => {
     }
 
     .ease-out\\! {
-      --tw-ease: var(--ease-out);
+      --tw-ease: var(--ease-out) !important;
       transition-timing-function: var(--ease-out) !important;
     }