diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9363fa3b4f0e..6ce4a9bff4dd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,7 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
-- Nothing yet!
+### Fixed
+
+- Use configured `--letter-spacing` values for custom font size utilities ([#15099](https://github.com/tailwindlabs/tailwindcss/pull/15099))
 
 ## [4.0.0-beta.1] - 2024-11-21
 
diff --git a/packages/tailwindcss/src/utilities.ts b/packages/tailwindcss/src/utilities.ts
index c5d9bdf3c6d4..d8e99dd7568f 100644
--- a/packages/tailwindcss/src/utilities.ts
+++ b/packages/tailwindcss/src/utilities.ts
@@ -4033,7 +4033,7 @@ export function createUtilities(theme: Theme) {
       let value = theme.resolveWith(
         candidate.value.value,
         ['--text'],
-        ['--line-height', '--tracking', '--font-weight'],
+        ['--line-height', '--letter-spacing', '--font-weight'],
       )
       if (value) {
         let [fontSize, options = {}] = Array.isArray(value) ? value : [value]
@@ -4067,7 +4067,9 @@ export function createUtilities(theme: Theme) {
           ),
           decl(
             'letter-spacing',
-            options['--tracking'] ? `var(--tw-tracking, ${options['--tracking']})` : undefined,
+            options['--letter-spacing']
+              ? `var(--tw-tracking, ${options['--letter-spacing']})`
+              : undefined,
           ),
           decl(
             'font-weight',
diff --git a/packages/tailwindcss/tests/ui.spec.ts b/packages/tailwindcss/tests/ui.spec.ts
index 445246beac4e..103307d78657 100644
--- a/packages/tailwindcss/tests/ui.spec.ts
+++ b/packages/tailwindcss/tests/ui.spec.ts
@@ -568,8 +568,8 @@ test('explicit tracking utilities are respected when overriding font-size', asyn
     `,
     css`
       @theme {
-        --text-sm--tracking: 5px;
-        --text-xl--tracking: 10px;
+        --text-sm--letter-spacing: 5px;
+        --text-xl--letter-spacing: 10px;
         --tracking-tight: 1px;
       }
     `,