diff --git a/editor/edit-post/sidebar/post-author/style.scss b/editor/edit-post/sidebar/post-author/style.scss
index a423d651051b82..879bdbeafc28dd 100644
--- a/editor/edit-post/sidebar/post-author/style.scss
+++ b/editor/edit-post/sidebar/post-author/style.scss
@@ -1,3 +1,4 @@
 .editor-post-author__select {
 	margin: -5px 0;
+	width: 100%;
 }