diff --git a/packages/material-ui/src/StepButton/StepButton.js b/packages/material-ui/src/StepButton/StepButton.js
index 174c46f433b36a..5200d4a9ddd1ec 100644
--- a/packages/material-ui/src/StepButton/StepButton.js
+++ b/packages/material-ui/src/StepButton/StepButton.js
@@ -16,7 +16,7 @@ export const styles = theme => ({
     boxSizing: 'content-box',
   },
   vertical: {
-    justifyContent: 'left',
+    justifyContent: 'flex-start',
   },
   touchRipple: {
     color: 'rgba(0, 0, 0, 0.3)',