diff --git a/app/code/Magento/Config/etc/system_file.xsd b/app/code/Magento/Config/etc/system_file.xsd
index 5a2b915262a9a..f1688b2e35371 100644
--- a/app/code/Magento/Config/etc/system_file.xsd
+++ b/app/code/Magento/Config/etc/system_file.xsd
@@ -474,7 +474,7 @@
             </xs:documentation>
         </xs:annotation>
         <xs:restriction base="xs:string">
-            <xs:pattern value="[A-Za-z0-9\\:]+" />
+            <xs:pattern value="[A-Za-z0-9_\\:]+" />
             <xs:minLength value="5" />
         </xs:restriction>
     </xs:simpleType>