diff --git a/lib/Iterator/ClassMapIterator.php b/lib/Iterator/ClassMapIterator.php
index f4e7699..07b25c4 100644
--- a/lib/Iterator/ClassMapIterator.php
+++ b/lib/Iterator/ClassMapIterator.php
@@ -45,7 +45,7 @@ static function (string $path): void {
 
         foreach ($this->classMap as $className => $path) {
             $path = PathNormalizer::resolvePath($path);
-            if ($this->pathCallback && ! ($this->pathCallback)($path)) {
+            if ($this->pathCallback && ! ($this->pathCallback)(PathNormalizer::normalize($path))) {
                 continue;
             }
 
diff --git a/lib/Iterator/FilteredComposerIterator.php b/lib/Iterator/FilteredComposerIterator.php
index bad886b..f813162 100644
--- a/lib/Iterator/FilteredComposerIterator.php
+++ b/lib/Iterator/FilteredComposerIterator.php
@@ -95,7 +95,7 @@ private function searchInClassMap(): Generator
                 continue;
             }
 
-            if ($this->pathCallback && ! ($this->pathCallback)($file)) {
+            if ($this->pathCallback && ! ($this->pathCallback)(PathNormalizer::normalize($file))) {
                 continue;
             }
 
diff --git a/lib/Iterator/OfflineIteratorTrait.php b/lib/Iterator/OfflineIteratorTrait.php
index 4957cc5..31a913b 100644
--- a/lib/Iterator/OfflineIteratorTrait.php
+++ b/lib/Iterator/OfflineIteratorTrait.php
@@ -77,7 +77,7 @@ public function notPath(array $patterns): self
 
     private function accept(string $path): bool
     {
-        if ($this->pathCallback && ! ($this->pathCallback)($path)) {
+        if ($this->pathCallback && ! ($this->pathCallback)(PathNormalizer::normalize($path))) {
             return false;
         }
 
diff --git a/lib/Iterator/Psr0Iterator.php b/lib/Iterator/Psr0Iterator.php
index 76ce3e4..7e2a73b 100644
--- a/lib/Iterator/Psr0Iterator.php
+++ b/lib/Iterator/Psr0Iterator.php
@@ -80,7 +80,7 @@ class_exists($class, true);
                 continue;
             }
 
-            if ($this->pathCallback && ! ($this->pathCallback)($path)) {
+            if ($this->pathCallback && ! ($this->pathCallback)(PathNormalizer::normalize($path))) {
                 continue;
             }
 
diff --git a/lib/Iterator/Psr4Iterator.php b/lib/Iterator/Psr4Iterator.php
index f759679..784e90c 100644
--- a/lib/Iterator/Psr4Iterator.php
+++ b/lib/Iterator/Psr4Iterator.php
@@ -80,7 +80,7 @@ class_exists($class, true);
                 continue;
             }
 
-            if ($this->pathCallback && ! ($this->pathCallback)($path)) {
+            if ($this->pathCallback && ! ($this->pathCallback)(PathNormalizer::normalize($path))) {
                 continue;
             }
 
diff --git a/lib/Iterator/RecursiveIterator.php b/lib/Iterator/RecursiveIterator.php
index 5855b18..95a7062 100644
--- a/lib/Iterator/RecursiveIterator.php
+++ b/lib/Iterator/RecursiveIterator.php
@@ -40,7 +40,7 @@ protected function getGenerator(): Generator
                 continue;
             }
 
-            if ($this->pathCallback && ! ($this->pathCallback)($path)) {
+            if ($this->pathCallback && ! ($this->pathCallback)(PathNormalizer::normalize($path))) {
                 continue;
             }
 
diff --git a/lib/PathNormalizer.php b/lib/PathNormalizer.php
index eed5ac4..88afca3 100644
--- a/lib/PathNormalizer.php
+++ b/lib/PathNormalizer.php
@@ -14,6 +14,14 @@
 
 final class PathNormalizer
 {
+    /**
+     * Normalizes path separator to '/'.
+     */
+    public static function normalize(string $path): string
+    {
+        return str_replace(DIRECTORY_SEPARATOR, '/', $path);
+    }
+
     /**
      * Resolve a path.
      *