diff --git a/src/wp-includes/js/customize-preview.js b/src/wp-includes/js/customize-preview.js
index a24be104f2..c5ea964461 100644
--- a/src/wp-includes/js/customize-preview.js
+++ b/src/wp-includes/js/customize-preview.js
@@ -451,6 +451,10 @@
 			if ( ! api.settings.theme.active ) {
 				queryParams.customize_theme = api.settings.theme.stylesheet;
 			}
+
+			// Ensure preview nonce is included with every customized request, to allow post data to be read.
+			queryParams.customize_preview_nonce = api.settings.nonce.preview;
+
 			urlParser.search = $.param( queryParams );
 			options.url = urlParser.href;
 		};