diff --git a/src/wp-admin/edit-form-blocks.php b/src/wp-admin/edit-form-blocks.php
index 5556bd7a62..6e353943b0 100644
--- a/src/wp-admin/edit-form-blocks.php
+++ b/src/wp-admin/edit-form-blocks.php
@@ -306,7 +306,7 @@ if ( false !== $color_palette ) {
 	$editor_settings['colors'] = $color_palette;
 }
 
-if ( ! empty( $font_sizes ) ) {
+if ( false !== $font_sizes ) {
 	$editor_settings['fontSizes'] = $font_sizes;
 }