diff --git a/composer.json b/composer.json
index f6cc9b9..3ec5766 100644
--- a/composer.json
+++ b/composer.json
@@ -25,6 +25,7 @@
     "require": {
         "php": ">=7.4",
         "consolidation/config": "^1.2.1 || ^2",
+        "symfony/event-dispatcher":"^5|| ^6",
         "symfony/filesystem": "^5.4 || ^6",
         "symfony/finder": "^5 || ^6"
     },
diff --git a/composer.lock b/composer.lock
index a1be500..1d688da 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "9b7a7566012d952bbf17cfcb02fed52d",
+    "content-hash": "7504c986f47d2aa268d067df3d16e26a",
     "packages": [
         {
             "name": "consolidation/config",
@@ -361,16 +361,16 @@
         },
         {
             "name": "symfony/event-dispatcher",
-            "version": "v5.4.9",
+            "version": "v5.4.26",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/event-dispatcher.git",
-                "reference": "8e6ce1cc0279e3ff3c8ff0f43813bc88d21ca1bc"
+                "reference": "5dcc00e03413f05c1e7900090927bb7247cb0aac"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/event-dispatcher/zipball/8e6ce1cc0279e3ff3c8ff0f43813bc88d21ca1bc",
-                "reference": "8e6ce1cc0279e3ff3c8ff0f43813bc88d21ca1bc",
+                "url": "https://api.github.com/repos/symfony/event-dispatcher/zipball/5dcc00e03413f05c1e7900090927bb7247cb0aac",
+                "reference": "5dcc00e03413f05c1e7900090927bb7247cb0aac",
                 "shasum": ""
             },
             "require": {
@@ -426,7 +426,7 @@
             "description": "Provides tools that allow your application components to communicate with each other by dispatching events and listening to them",
             "homepage": "https://symfony.com",
             "support": {
-                "source": "https://github.com/symfony/event-dispatcher/tree/v5.4.9"
+                "source": "https://github.com/symfony/event-dispatcher/tree/v5.4.26"
             },
             "funding": [
                 {
@@ -442,7 +442,7 @@
                     "type": "tidelift"
                 }
             ],
-            "time": "2022-05-05T16:45:39+00:00"
+            "time": "2023-07-06T06:34:20+00:00"
         },
         {
             "name": "symfony/event-dispatcher-contracts",
@@ -817,16 +817,16 @@
         },
         {
             "name": "symfony/polyfill-php80",
-            "version": "v1.26.0",
+            "version": "v1.28.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/polyfill-php80.git",
-                "reference": "cfa0ae98841b9e461207c13ab093d76b0fa7bace"
+                "reference": "6caa57379c4aec19c0a12a38b59b26487dcfe4b5"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/polyfill-php80/zipball/cfa0ae98841b9e461207c13ab093d76b0fa7bace",
-                "reference": "cfa0ae98841b9e461207c13ab093d76b0fa7bace",
+                "url": "https://api.github.com/repos/symfony/polyfill-php80/zipball/6caa57379c4aec19c0a12a38b59b26487dcfe4b5",
+                "reference": "6caa57379c4aec19c0a12a38b59b26487dcfe4b5",
                 "shasum": ""
             },
             "require": {
@@ -835,7 +835,7 @@
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-main": "1.26-dev"
+                    "dev-main": "1.28-dev"
                 },
                 "thanks": {
                     "name": "symfony/polyfill",
@@ -880,7 +880,7 @@
                 "shim"
             ],
             "support": {
-                "source": "https://github.com/symfony/polyfill-php80/tree/v1.26.0"
+                "source": "https://github.com/symfony/polyfill-php80/tree/v1.28.0"
             },
             "funding": [
                 {
@@ -896,7 +896,7 @@
                     "type": "tidelift"
                 }
             ],
-            "time": "2022-05-10T07:21:04+00:00"
+            "time": "2023-01-26T09:26:14+00:00"
         }
     ],
     "packages-dev": [
diff --git a/src/Events/AliasNotFoundEvent.php b/src/Events/AliasNotFoundEvent.php
new file mode 100644
index 0000000..190d44b
--- /dev/null
+++ b/src/Events/AliasNotFoundEvent.php
@@ -0,0 +1,36 @@
+<?php
+
+namespace Consolidation\SiteAlias\Events;
+
+use Consolidation\SiteAlias\SiteAlias;
+use Symfony\Contracts\EventDispatcher\Event;
+
+class AliasNotFoundEvent extends Event
+{
+
+    protected $aliasName;
+
+    protected $alias = false;
+
+    const NAME = 'alias-not-found';
+
+    public function __construct($aliasName)
+    {
+        $this->aliasName = $aliasName;
+    }
+
+    public function setAlias(SiteAlias $alias)
+    {
+        $this->alias = $alias;
+    }
+
+    public function hasAlias()
+    {
+        return $this->alias !== false;
+    }
+
+    public function getAlias()
+    {
+        return $this->alias;
+    }
+}
diff --git a/src/SiteAliasManager.php b/src/SiteAliasManager.php
index 4105a2b..fe7e906 100644
--- a/src/SiteAliasManager.php
+++ b/src/SiteAliasManager.php
@@ -1,6 +1,9 @@
 <?php
 namespace Consolidation\SiteAlias;
 
+use Consolidation\SiteAlias\Events\AliasNotFoundEvent;
+use Symfony\Component\EventDispatcher\EventDispatcher;
+
 /**
  * Site Alias manager
  */
@@ -10,6 +13,7 @@ class SiteAliasManager implements SiteAliasManagerInterface, SiteAliasManagerIni
     protected $selfSiteAlias;
     protected $specParser;
     protected $root = '';
+    protected $dispatcher;
 
     /**
      * Constructor for SiteAliasManager
@@ -21,6 +25,7 @@ public function __construct($aliasLoader = null, $root = '')
         $this->aliasLoader = $aliasLoader ?: new SiteAliasFileLoader();
         $this->specParser = new SiteSpecParser();
         $this->selfSiteAlias = new SiteAlias();
+        $this->dispatcher = new EventDispatcher();
         $this->setRoot($root);
     }
 
@@ -97,7 +102,16 @@ public function searchLocations()
     public function get($name)
     {
         if (SiteAliasName::isAliasName($name)) {
-            return $this->getAlias($name);
+            $alias =  $this->getAlias($name);
+            if (!$alias) {
+                //TODO, call all registered listeners here - if none of them return an alias, we return false
+                $event = new AliasNotFoundEvent($name);
+                $this->dispatcher->dispatch($event, AliasNotFoundEvent::NAME);
+                if ($event->hasAlias()) {
+                    return $event->getAlias();
+                }
+                return false;
+            }
         }
 
         if ($this->specParser->validSiteSpec($name)) {
@@ -212,4 +226,9 @@ public function listAllFilePaths($location = '')
     {
         return $this->aliasLoader->listAll($location);
     }
+
+    public function addListener($hook, callable $callback)
+    {
+        $this->dispatcher->addListener($hook, $callback);
+    }
 }
diff --git a/tests/SiteAliasManagerTest.php b/tests/SiteAliasManagerTest.php
index d80df01..915c856 100644
--- a/tests/SiteAliasManagerTest.php
+++ b/tests/SiteAliasManagerTest.php
@@ -1,9 +1,12 @@
 <?php
 namespace Consolidation\SiteAlias;
 
+use Consolidation\SiteAlias\Events\AliasNotFoundEvent;
 use Consolidation\SiteAlias\Util\YamlDataFileLoader;
 use PHPUnit\Framework\TestCase;
+use Symfony\Component\EventDispatcher\GenericEvent;
 use Symfony\Component\Yaml\Yaml;
+use Symfony\Contracts\EventDispatcher\Event;
 
 class SiteAliasManagerTest extends TestCase
 {
@@ -162,6 +165,26 @@ public function testGetMultiple()
         $this->assertEquals('@other.single.dev,@other.single.other', implode(',', $allNames));
     }
 
+    /**
+     * This tests registering a custom site alias resolver when sites are not found using the standard resolution methods
+     *
+     */
+    public function testEventListener()
+    {
+        /* @var SiteAlias $alias */
+        $alias = $this->manager->get('@nonexistent.me');
+        $this->assertFalse($alias, false);
+        $this->manager->addListener(
+            AliasNotFoundEvent::NAME,
+            function (AliasNotFoundEvent $event) {
+                $event->setAlias(new SiteAlias(['test' => 'isset']));
+            }
+        );
+
+        $alias = $this->manager->get('@nonexistent.site');
+        $this->assertEquals('isset', $alias->get('test'));
+    }
+
     /**
      * @covers \Consolidation\SiteAlias\SiteAlias::root()
      */