diff --git src/bp-members/screens/register.php src/bp-members/screens/register.php
index f954f3f41..54b6facd5 100644
--- src/bp-members/screens/register.php
+++ src/bp-members/screens/register.php
@@ -155,11 +155,22 @@ function bp_core_screen_signup() {
 				 * Filters the error message in the loop.
 				 *
 				 * @since 1.5.0
+				 * @since 8.0.0 Adds the `$fieldname` parameter to the anonymous function.
 				 *
-				 * @param string $value Error message wrapped in html.
+				 * @param string $value     Error message wrapped in html.
+				 * @param string $fieldname The name of the signup field.
 				 */
-				add_action( 'bp_' . $fieldname . '_errors', function() use ( $error_message ) {
-					echo apply_filters( 'bp_members_signup_error_message', "<div class=\"error\">" . $error_message . "</div>" );
+				add_action( 'bp_' . $fieldname . '_errors', function() use ( $error_message, $fieldname ) {
+					/**
+					 * Filter here to edit the error message about the invalid field value.
+					 *
+					 * @since 1.5.0
+					 * @since 8.0.0 Adds the `$fieldname` parameter.
+					 *
+					 * @param string $value     Error message wrapped in html.
+					 * @param string $fieldname The name of the signup field.
+					 */
+					echo apply_filters( 'bp_members_signup_error_message', "<div class=\"error\">" . $error_message . "</div>", $fieldname );
 				} );
 			}
 		} else {