diff --git a/packages/mui-joy/src/Textarea/textareaClasses.ts b/packages/mui-joy/src/Textarea/textareaClasses.ts
index 3baca3c7b716df..f2fc47955b92fb 100644
--- a/packages/mui-joy/src/Textarea/textareaClasses.ts
+++ b/packages/mui-joy/src/Textarea/textareaClasses.ts
@@ -31,6 +31,10 @@ export interface TextareaClasses {
   sizeMd: string;
   /** Styles applied to the root element if `size="lg"`. */
   sizeLg: string;
+  /** Styles applied to the startDecorator element if supplied. */
+  startDecorator: string;
+  /** Styles applied to the endDecorator element if supplied. */
+  endDecorator: string;
   /** Styles applied to the root element if `variant="plain"`. */
   variantPlain: string;
   /** Styles applied to the root element if `variant="outlined"`. */
@@ -61,6 +65,8 @@ const textareaClasses: TextareaClasses = generateUtilityClasses('JoyTextarea', [
   'sizeSm',
   'sizeMd',
   'sizeLg',
+  'startDecorator',
+  'endDecorator',
   'variantPlain',
   'variantOutlined',
   'variantSoft',