diff --git a/core/src/components/button/button.tsx b/core/src/components/button/button.tsx
index 9eecd0d2c62..74e9d47e2f7 100644
--- a/core/src/components/button/button.tsx
+++ b/core/src/components/button/button.tsx
@@ -406,7 +406,7 @@ export class Button implements ComponentInterface, AnchorInterface, ButtonInterf
           onBlur={this.onBlur}
           {...inheritedAttributes}
         >
-          <span class="button-inner">
+          <span class="button-inner" part="inner">
             <slot name="icon-only" onSlotchange={this.slotChanged}></slot>
             <slot name="start"></slot>
             <slot></slot>