diff --git a/packages/material-ui/src/ButtonGroup/ButtonGroup.d.ts b/packages/material-ui/src/ButtonGroup/ButtonGroup.d.ts
index fa0899d9e0bd56..745c31d4355a2a 100644
--- a/packages/material-ui/src/ButtonGroup/ButtonGroup.d.ts
+++ b/packages/material-ui/src/ButtonGroup/ButtonGroup.d.ts
@@ -31,7 +31,8 @@ export type ButtonGroupClassKey =
   | 'groupedOutlinedSecondary'
   | 'groupedContained'
   | 'groupedContainedPrimary'
-  | 'groupedContainedSecondary';
+  | 'groupedContainedSecondary'
+  | 'disabled';
 
 export type ButtonGroupProps<
   D extends React.ElementType = ButtonGroupTypeMap['defaultComponent'],