diff --git a/.changeset/brown-ducks-lick.md b/.changeset/brown-ducks-lick.md
new file mode 100644
index 00000000000..524589f6b97
--- /dev/null
+++ b/.changeset/brown-ducks-lick.md
@@ -0,0 +1,5 @@
+---
+'@primer/react': patch
+---
+
+DialogV2: Fix CSS issue where `flex-grow` wasn't getting applied via classname
diff --git a/packages/react/src/Dialog/Dialog.module.css b/packages/react/src/Dialog/Dialog.module.css
index 89085c7110a..a616afca598 100644
--- a/packages/react/src/Dialog/Dialog.module.css
+++ b/packages/react/src/Dialog/Dialog.module.css
@@ -65,10 +65,6 @@
     justify-content: flex-end;
   }
 
-  .DialogOverflowWrapper {
-    flex-grow: 1;
-  }
-
   @media (max-width: 767px) {
     &[data-position-narrow='center'] {
       align-items: center;
@@ -212,6 +208,10 @@
   }
 }
 
+.DialogOverflowWrapper {
+  flex-grow: 1;
+}
+
 .Header {
   z-index: 1;
   padding: var(--base-size-8);
diff --git a/packages/react/src/Dialog/Dialog.tsx b/packages/react/src/Dialog/Dialog.tsx
index 25d04a75b8b..9a027ffabb2 100644
--- a/packages/react/src/Dialog/Dialog.tsx
+++ b/packages/react/src/Dialog/Dialog.tsx
@@ -527,7 +527,7 @@ const _Dialog = React.forwardRef<HTMLDivElement, React.PropsWithChildren<DialogP
             className={clsx(className, enabled && classes.Dialog)}
           >
             {header}
-            <ScrollableRegion aria-labelledby={dialogLabelId} className="DialogOverflowWrapper">
+            <ScrollableRegion aria-labelledby={dialogLabelId} className={classes.DialogOverflowWrapper}>
               {body}
             </ScrollableRegion>
             {footer}