diff --git a/extensions/lang-english/locale/validation.yml b/extensions/lang-english/locale/validation.yml
index 6d0b0a5ac..7a4847d22 100644
--- a/extensions/lang-english/locale/validation.yml
+++ b/extensions/lang-english/locale/validation.yml
@@ -43,6 +43,7 @@ validation:
   regex: "The :attribute format is invalid."
   required: "The :attribute field is required."
   required_if: "The :attribute field is required when :other is :value."
+  required_unless: "The :attribute field is required unless :other is in :values."
   required_with: "The :attribute field is required when :values is present."
   required_with_all: "The :attribute field is required when :values is present."
   required_without: "The :attribute field is required when :values is not present."