diff --git a/src/Date.php b/src/Date.php
index 449948b..db1bcba 100644
--- a/src/Date.php
+++ b/src/Date.php
@@ -377,11 +377,26 @@ public static function getLocale()
     public static function setLocale($locale)
     {
         // Use RFC 5646 for filenames.
-        $resource = __DIR__.'/Lang/'.str_replace('_', '-', $locale).'.php';
+        $files = array_unique([
+            str_replace('_', '-', $locale),
+            static::getLanguageFromLocale($locale),
+            str_replace('_', '-', static::getFallbackLocale()),
+            static::getLanguageFromLocale(static::getFallbackLocale()),
+        ]);
 
-        if (! file_exists($resource)) {
-            static::setLocale(static::getFallbackLocale());
+        $found = false;
 
+        foreach ($files as $file) {
+            $resource = __DIR__.'/Lang/'.$file.'.php';
+
+            if (file_exists($resource)) {
+                $found = true;
+                $locale = $file;
+                break;
+            }
+        }
+
+        if (! $found) {
             return;
         }
 
@@ -505,4 +520,17 @@ public static function translateTimeString($time)
 
         return $translated;
     }
+
+    /**
+     * Get the language portion of the locale.
+     *
+     * @param string $locale
+     * @return string
+     */
+    public static function getLanguageFromLocale($locale)
+    {
+        $parts = explode('_', str_replace('-', '_', $locale));
+
+        return $parts[0];
+    }
 }
diff --git a/tests/TranslationTest.php b/tests/TranslationTest.php
index 2523840..b482f21 100644
--- a/tests/TranslationTest.php
+++ b/tests/TranslationTest.php
@@ -30,6 +30,15 @@ public function testFallback()
         $this->assertSame('5 years ago', $date->ago());
     }
 
+    public function testFallbackWithRegion()
+    {
+        Date::setFallbackLocale('en_US');
+        Date::setLocale('xx');
+
+        $date = Date::parse('-5 years');
+        $this->assertSame('5 years ago', $date->ago());
+    }
+
     public function testMultiplePluralForms()
     {
         Date::setLocale('hr');