diff --git a/docs/data/material/components/button-group/SplitButton.js b/docs/data/material/components/button-group/SplitButton.js
index f4b59dfb1f3d77..f1d31e4e595568 100644
--- a/docs/data/material/components/button-group/SplitButton.js
+++ b/docs/data/material/components/button-group/SplitButton.js
@@ -53,6 +53,9 @@ export default function SplitButton() {
         </Button>
       </ButtonGroup>
       <Popper
+        sx={{
+          zIndex: 1,
+        }}
         open={open}
         anchorEl={anchorRef.current}
         role={undefined}
diff --git a/docs/data/material/components/button-group/SplitButton.tsx b/docs/data/material/components/button-group/SplitButton.tsx
index 0397081c2962ca..2d58c3daa3c926 100644
--- a/docs/data/material/components/button-group/SplitButton.tsx
+++ b/docs/data/material/components/button-group/SplitButton.tsx
@@ -59,6 +59,9 @@ export default function SplitButton() {
         </Button>
       </ButtonGroup>
       <Popper
+        sx={{
+          zIndex: 1,
+        }}
         open={open}
         anchorEl={anchorRef.current}
         role={undefined}