diff --git a/src/Standards/PSR2/Sniffs/Classes/ClassDeclarationSniff.php b/src/Standards/PSR2/Sniffs/Classes/ClassDeclarationSniff.php
index 22cf2abc0f..d356e76ef2 100644
--- a/src/Standards/PSR2/Sniffs/Classes/ClassDeclarationSniff.php
+++ b/src/Standards/PSR2/Sniffs/Classes/ClassDeclarationSniff.php
@@ -314,7 +314,8 @@ public function processOpen(File $phpcsFile, $stackPtr)
             if ($checkingImplements === true
                 && $multiLineImplements === true
                 && ($tokens[($className - 1)]['code'] !== T_NS_SEPARATOR
-                || $tokens[($className - 2)]['code'] !== T_STRING)
+                || ($tokens[($className - 2)]['code'] !== T_STRING
+                && $tokens[($className - 2)]['code'] !== T_NAMESPACE))
             ) {
                 $prev = $phpcsFile->findPrevious(
                     [
@@ -397,9 +398,10 @@ public function processOpen(File $phpcsFile, $stackPtr)
                     }
                 }//end if
             } else if ($tokens[($className - 1)]['code'] !== T_NS_SEPARATOR
-                || $tokens[($className - 2)]['code'] !== T_STRING
+                || ($tokens[($className - 2)]['code'] !== T_STRING
+                && $tokens[($className - 2)]['code'] !== T_NAMESPACE)
             ) {
-                // Not part of a longer fully qualified class name.
+                // Not part of a longer fully qualified or namespace relative class name.
                 if ($tokens[($className - 1)]['code'] === T_COMMA
                     || ($tokens[($className - 1)]['code'] === T_NS_SEPARATOR
                     && $tokens[($className - 2)]['code'] === T_COMMA)
diff --git a/src/Standards/PSR2/Tests/Classes/ClassDeclarationUnitTest.inc b/src/Standards/PSR2/Tests/Classes/ClassDeclarationUnitTest.inc
index 303846b721..962f182dfd 100644
--- a/src/Standards/PSR2/Tests/Classes/ClassDeclarationUnitTest.inc
+++ b/src/Standards/PSR2/Tests/Classes/ClassDeclarationUnitTest.inc
@@ -282,3 +282,14 @@ readonly
     class ReadonlyClassWithComment
     {
     }
+
+// Safeguard against fixer conflict when there are namespace relative interface names in extends.
+interface FooBar extends namespace\BarFoo
+{
+}
+
+// Safeguard against fixer conflict when there are namespace relative interface names in a multi-line implements.
+class BarFoo implements
+    namespace\BarFoo
+{
+}
diff --git a/src/Standards/PSR2/Tests/Classes/ClassDeclarationUnitTest.inc.fixed b/src/Standards/PSR2/Tests/Classes/ClassDeclarationUnitTest.inc.fixed
index 78dbbbb4b2..8725c4fac7 100644
--- a/src/Standards/PSR2/Tests/Classes/ClassDeclarationUnitTest.inc.fixed
+++ b/src/Standards/PSR2/Tests/Classes/ClassDeclarationUnitTest.inc.fixed
@@ -270,3 +270,14 @@ readonly
     class ReadonlyClassWithComment
     {
     }
+
+// Safeguard against fixer conflict when there are namespace relative interface names in extends.
+interface FooBar extends namespace\BarFoo
+{
+}
+
+// Safeguard against fixer conflict when there are namespace relative interface names in a multi-line implements.
+class BarFoo implements
+    namespace\BarFoo
+{
+}