diff --git a/custom-standards/Flyeralarm/Sniffs/Classes/FullyQualifiedSniff.php b/custom-standards/Flyeralarm/Sniffs/Classes/FullyQualifiedSniff.php
index 47ab8a2..1cbaf6d 100644
--- a/custom-standards/Flyeralarm/Sniffs/Classes/FullyQualifiedSniff.php
+++ b/custom-standards/Flyeralarm/Sniffs/Classes/FullyQualifiedSniff.php
@@ -13,7 +13,7 @@ class FullyQualifiedSniff implements Sniff
      */
     public function register()
     {
-        return array(T_DOUBLE_COLON, T_NEW, T_EXTENDS);
+        return array(T_DOUBLE_COLON, T_NEW, T_EXTENDS, T_IMPLEMENTS);
     }
 
     /**
@@ -63,6 +63,7 @@ private function getClassCall(File $phpcsFile, $stackPtr): string
                 );
 
             case T_EXTENDS:
+            case T_IMPLEMENTS:
                 $tokensAsString = $phpcsFile->getTokensAsString(
                     $stackPtr,
                     $phpcsFile->findEndOfStatement($stackPtr) - $stackPtr
diff --git a/tests/rules/classes/allowed/FullyQualifiedSniff.php b/tests/rules/classes/allowed/FullyQualifiedSniff.php
index cbebc25..40adf13 100644
--- a/tests/rules/classes/allowed/FullyQualifiedSniff.php
+++ b/tests/rules/classes/allowed/FullyQualifiedSniff.php
@@ -4,10 +4,11 @@
 
 namespace flyeralarm\Test;
 
+use IteratorAggregate;
 use RuntimeException;
 use stdClass;
 
-class FullyQualifiedSniff extends stdClass
+class FullyQualifiedSniff extends stdClass implements IteratorAggregate
 {
     public function a()
     {
@@ -21,4 +22,8 @@ public function b()
             'We can\'t explain'
         );
     }
+
+    public function getIterator()
+    {
+    }
 }
diff --git a/tests/rules/classes/not-allowed/FullyQualifiedSniffImplements.php b/tests/rules/classes/not-allowed/FullyQualifiedSniffImplements.php
new file mode 100644
index 0000000..786d7c0
--- /dev/null
+++ b/tests/rules/classes/not-allowed/FullyQualifiedSniffImplements.php
@@ -0,0 +1,12 @@
+<?php
+
+// @expectedError Qualifier should be replaced with an import: "implements \IteratorAggregate"
+
+namespace flyeralarm\Test;
+
+class FullyQualifiedSniffImplements implements \IteratorAggregate
+{
+    public function getIterator()
+    {
+    }
+}