diff --git a/.changeset/chilly-phones-explode.md b/.changeset/chilly-phones-explode.md
new file mode 100644
index 00000000000..1733d38765a
--- /dev/null
+++ b/.changeset/chilly-phones-explode.md
@@ -0,0 +1,5 @@
+---
+"@primer/react": patch
+---
+
+Bug fix: `ButtonBase` sx base styles leaking into CSS modules feat flag
diff --git a/packages/react/src/Button/ButtonBase.tsx b/packages/react/src/Button/ButtonBase.tsx
index f64137b8433..752525b1ad9 100644
--- a/packages/react/src/Button/ButtonBase.tsx
+++ b/packages/react/src/Button/ButtonBase.tsx
@@ -118,7 +118,7 @@ const ButtonBase = forwardRef(
           >
             <Box
               as={Component}
-              sx={sxStyles}
+              sx={sxProp}
               aria-disabled={loading ? true : undefined}
               {...rest}
               ref={innerRef}