diff --git a/NEWS b/NEWS
index 9d66e8e3e59..59d46ef25dd 100644
--- a/NEWS
+++ b/NEWS
@@ -37,6 +37,10 @@ PHP                                                                        NEWS
   . Fixed bug GH-20602 (imagescale overflow with large height values).
     (David Carlier)
 
+- Intl:
+  . Fixed bug GH-20426 (Spoofchecker::setRestrictionLevel() error message
+    suggests missing constants). (DanielEScherzer)
+
 - LibXML:
   . Fix some deprecations on newer libxml versions regarding input
     buffer/parser handling. (ndossche)
diff --git a/ext/intl/spoofchecker/spoofchecker_main.c b/ext/intl/spoofchecker/spoofchecker_main.c
index afea503bc0e..0ead525aed6 100644
--- a/ext/intl/spoofchecker/spoofchecker_main.c
+++ b/ext/intl/spoofchecker/spoofchecker_main.c
@@ -156,8 +156,8 @@ PHP_METHOD(Spoofchecker, setRestrictionLevel)
 			USPOOF_MINIMALLY_RESTRICTIVE != level &&
 			USPOOF_UNRESTRICTIVE != level) {
 		zend_argument_value_error(1, "must be one of Spoofchecker::ASCII, Spoofchecker::SINGLE_SCRIPT_RESTRICTIVE, "
-			"Spoofchecker::SINGLE_HIGHLY_RESTRICTIVE, Spoofchecker::SINGLE_MODERATELY_RESTRICTIVE, "
-			"Spoofchecker::SINGLE_MINIMALLY_RESTRICTIVE, or Spoofchecker::UNRESTRICTIVE");
+			"Spoofchecker::HIGHLY_RESTRICTIVE, Spoofchecker::MODERATELY_RESTRICTIVE, "
+			"Spoofchecker::MINIMALLY_RESTRICTIVE, or Spoofchecker::UNRESTRICTIVE");
 		RETURN_THROWS();
 	}
 
diff --git a/ext/intl/tests/spoofchecker_unknown_restriction_level.phpt b/ext/intl/tests/spoofchecker_unknown_restriction_level.phpt
index e8ed48d60a3..6b7e9474755 100644
--- a/ext/intl/tests/spoofchecker_unknown_restriction_level.phpt
+++ b/ext/intl/tests/spoofchecker_unknown_restriction_level.phpt
@@ -20,4 +20,4 @@ try {
 
 ?>
 --EXPECT--
-Spoofchecker::setRestrictionLevel(): Argument #1 ($level) must be one of Spoofchecker::ASCII, Spoofchecker::SINGLE_SCRIPT_RESTRICTIVE, Spoofchecker::SINGLE_HIGHLY_RESTRICTIVE, Spoofchecker::SINGLE_MODERATELY_RESTRICTIVE, Spoofchecker::SINGLE_MINIMALLY_RESTRICTIVE, or Spoofchecker::UNRESTRICTIVE
+Spoofchecker::setRestrictionLevel(): Argument #1 ($level) must be one of Spoofchecker::ASCII, Spoofchecker::SINGLE_SCRIPT_RESTRICTIVE, Spoofchecker::HIGHLY_RESTRICTIVE, Spoofchecker::MODERATELY_RESTRICTIVE, Spoofchecker::MINIMALLY_RESTRICTIVE, or Spoofchecker::UNRESTRICTIVE