diff --git a/build/code_sniffer/ruleset-php-strict.xml b/build/code_sniffer/ruleset-php-strict.xml
index 65b6763c57..3387a2c567 100644
--- a/build/code_sniffer/ruleset-php-strict.xml
+++ b/build/code_sniffer/ruleset-php-strict.xml
@@ -16,6 +16,10 @@
  </rule>
  -->
 
+ <!-- A file MUST not contain more than one class/interface -->
+ <rule ref="Generic.Files.OneClassPerFile" />
+ <rule ref="Generic.Files.OneInterfacePerFile" />
+
  <!-- The PHP constants true, false, and null MUST be in lower case. -->
  <rule ref="Generic.PHP.LowerCaseConstant" />