diff --git a/packages/react-dev-utils/webpackHotDevClient.js b/packages/react-dev-utils/webpackHotDevClient.js
index 645073f2486..c76d5c6fe86 100644
--- a/packages/react-dev-utils/webpackHotDevClient.js
+++ b/packages/react-dev-utils/webpackHotDevClient.js
@@ -67,7 +67,7 @@ function addOverlayDivTo(iframe) {
   div.style.overflowY = 'auto';
   div.style.padding = '0.5rem';
   div.style.boxSizing = 'border-box';
-  div.style.textAlign = 'start';
+  div.style.textAlign = 'left';
   div.style.fontFamily = 'Consolas, Menlo, monospace';
   div.style.fontSize = '11px';
   div.style.whiteSpace = 'pre-wrap';
diff --git a/packages/react-error-overlay/src/styles.js b/packages/react-error-overlay/src/styles.js
index 88213c3a0c3..916513f3c50 100644
--- a/packages/react-error-overlay/src/styles.js
+++ b/packages/react-error-overlay/src/styles.js
@@ -37,7 +37,7 @@ const containerStyle = {
   'overflow-y': 'auto',
   padding: '0.5rem',
   'box-sizing': 'border-box',
-  'text-align': 'start',
+  'text-align': 'left',
   'font-family': 'Consolas, Menlo, monospace',
   'font-size': '11px',
   'white-space': 'pre-wrap',