diff --git a/src/applications/differential/phid/DifferentialPHIDTypeRevision.php b/src/applications/differential/phid/DifferentialPHIDTypeRevision.php
--- a/src/applications/differential/phid/DifferentialPHIDTypeRevision.php
+++ b/src/applications/differential/phid/DifferentialPHIDTypeRevision.php
@@ -12,6 +12,10 @@
     return pht('Revision');
   }
 
+  public function getPHIDTypeApplicationClass() {
+    return 'PhabricatorApplicationDifferential';
+  }
+
   public function newObject() {
     return new DifferentialRevision();
   }
diff --git a/src/applications/maniphest/phid/ManiphestPHIDTypeTask.php b/src/applications/maniphest/phid/ManiphestPHIDTypeTask.php
--- a/src/applications/maniphest/phid/ManiphestPHIDTypeTask.php
+++ b/src/applications/maniphest/phid/ManiphestPHIDTypeTask.php
@@ -12,6 +12,10 @@
     return pht('Task');
   }
 
+  public function getPHIDTypeApplicationClass() {
+    return 'PhabricatorApplicationManiphest';
+  }
+
   public function newObject() {
     return new ManiphestTask();
   }
diff --git a/src/applications/people/phid/PhabricatorPeoplePHIDTypeUser.php b/src/applications/people/phid/PhabricatorPeoplePHIDTypeUser.php
--- a/src/applications/people/phid/PhabricatorPeoplePHIDTypeUser.php
+++ b/src/applications/people/phid/PhabricatorPeoplePHIDTypeUser.php
@@ -12,6 +12,10 @@
     return pht('User');
   }
 
+  public function getPHIDTypeApplicationClass() {
+    return 'PhabricatorApplicationPeople';
+  }
+
   public function getTypeIcon() {
     return 'policy-all';
   }
diff --git a/src/applications/phid/type/PhabricatorPHIDType.php b/src/applications/phid/type/PhabricatorPHIDType.php
--- a/src/applications/phid/type/PhabricatorPHIDType.php
+++ b/src/applications/phid/type/PhabricatorPHIDType.php
@@ -13,6 +13,20 @@
     return null;
   }
 
+
+  /**
+   * Get the class name for the application this type belongs to.
+   *
+   * @return string|null Class name of the corresponding application, or null
+   *   if the type is not bound to an application.
+   */
+  public function getPHIDTypeApplicationClass() {
+    // TODO: Some day this should probably be abstract, but for now it only
+    // affects global search and there's no real burning need to go classify
+    // every PHID type.
+    return null;
+  }
+
   /**
    * Build a @{class:PhabricatorPolicyAwareQuery} to load objects of this type
    * by PHID.
@@ -103,6 +117,15 @@
     throw new Exception("Not implemented!");
   }
 
+
+  /**
+   * Get all known PHID types.
+   *
+   * To get PHID types a given user has access to, see
+   * @{method:getAllInstalledTypes}.
+   *
+   * @return dict<string, PhabricatorPHIDType> Map of type constants to types.
+   */
   public static function getAllTypes() {
     static $types;
     if ($types === null) {
@@ -133,4 +156,48 @@
     return $types;
   }
 
+
+  /**
+   * Get all PHID types of applications installed for a given viewer.
+   *
+   * @param PhabricatorUser Viewing user.
+   * @return dict<string, PhabricatorPHIDType> Map of constants to installed
+   *  types.
+   */
+  public static function getAllInstalledTypes(PhabricatorUser $viewer) {
+    $all_types = self::getAllTypes();
+
+    $installed_types = array();
+
+    $app_classes = array();
+    foreach ($all_types as $key => $type) {
+      $app_class = $type->getPHIDTypeApplicationClass();
+
+      if ($app_class === null) {
+        // If the PHID type isn't bound to an application, include it as
+        // installed.
+        $installed_types[$key] = $type;
+        continue;
+      }
+
+      // Otherwise, we need to check if this application is installed before
+      // including the PHID type.
+      $app_classes[$app_class][$key] = $type;
+    }
+
+    if ($app_classes) {
+      $apps = id(new PhabricatorApplicationQuery())
+        ->setViewer($viewer)
+        ->withInstalled(true)
+        ->withClasses(array_keys($app_classes))
+        ->execute();
+
+      foreach ($apps as $app_class => $app) {
+        $installed_types += $app_classes[$app_class];
+      }
+    }
+
+    return $installed_types;
+  }
+
 }
diff --git a/src/applications/pholio/phid/PholioPHIDTypeMock.php b/src/applications/pholio/phid/PholioPHIDTypeMock.php
--- a/src/applications/pholio/phid/PholioPHIDTypeMock.php
+++ b/src/applications/pholio/phid/PholioPHIDTypeMock.php
@@ -12,6 +12,10 @@
     return pht('Mock');
   }
 
+  public function getPHIDTypeApplicationClass() {
+    return 'PhabricatorApplicationPholio';
+  }
+
   public function newObject() {
     return new PholioMock();
   }
diff --git a/src/applications/phriction/phid/PhrictionPHIDTypeDocument.php b/src/applications/phriction/phid/PhrictionPHIDTypeDocument.php
--- a/src/applications/phriction/phid/PhrictionPHIDTypeDocument.php
+++ b/src/applications/phriction/phid/PhrictionPHIDTypeDocument.php
@@ -12,6 +12,10 @@
     return pht('Wiki Document');
   }
 
+  public function getPHIDTypeApplicationClass() {
+    return 'PhabricatorApplicationPhriction';
+  }
+
   public function newObject() {
     return new PhrictionDocument();
   }
diff --git a/src/applications/ponder/phid/PonderPHIDTypeQuestion.php b/src/applications/ponder/phid/PonderPHIDTypeQuestion.php
--- a/src/applications/ponder/phid/PonderPHIDTypeQuestion.php
+++ b/src/applications/ponder/phid/PonderPHIDTypeQuestion.php
@@ -12,6 +12,10 @@
     return pht('Question');
   }
 
+  public function getPHIDTypeApplicationClass() {
+    return 'PhabricatorApplicationPonder';
+  }
+
   public function newObject() {
     return new PonderQuestion();
   }
diff --git a/src/applications/project/phid/PhabricatorProjectPHIDTypeProject.php b/src/applications/project/phid/PhabricatorProjectPHIDTypeProject.php
--- a/src/applications/project/phid/PhabricatorProjectPHIDTypeProject.php
+++ b/src/applications/project/phid/PhabricatorProjectPHIDTypeProject.php
@@ -12,6 +12,10 @@
     return pht('Project');
   }
 
+  public function getPHIDTypeApplicationClass() {
+    return 'PhabricatorApplicationProject';
+  }
+
   public function getTypeIcon() {
     return 'policy-project';
   }
diff --git a/src/applications/repository/phid/PhabricatorRepositoryPHIDTypeCommit.php b/src/applications/repository/phid/PhabricatorRepositoryPHIDTypeCommit.php
--- a/src/applications/repository/phid/PhabricatorRepositoryPHIDTypeCommit.php
+++ b/src/applications/repository/phid/PhabricatorRepositoryPHIDTypeCommit.php
@@ -12,6 +12,10 @@
     return pht('Commit');
   }
 
+  public function getPHIDTypeApplicationClass() {
+    return 'PhabricatorApplicationDiffusion';
+  }
+
   public function newObject() {
     return new PhabricatorRepositoryCommit();
   }
diff --git a/src/applications/search/query/PhabricatorSearchApplicationSearchEngine.php b/src/applications/search/query/PhabricatorSearchApplicationSearchEngine.php
--- a/src/applications/search/query/PhabricatorSearchApplicationSearchEngine.php
+++ b/src/applications/search/query/PhabricatorSearchApplicationSearchEngine.php
@@ -96,7 +96,7 @@
     $type_values = $saved->getParameter('types', array());
     $type_values = array_fuse($type_values);
 
-    $types = self::getIndexableDocumentTypes();
+    $types = self::getIndexableDocumentTypes($this->requireViewer());
 
     $types_control = id(new AphrontFormCheckboxControl())
       ->setLabel(pht('Document Types'));
@@ -190,18 +190,21 @@
     return parent::buildSavedQueryFromBuiltin($query_key);
   }
 
-  public static function getIndexableDocumentTypes() {
+  public static function getIndexableDocumentTypes(
+    PhabricatorUser $viewer = null) {
+
     // TODO: This is inelegant and not very efficient, but gets us reasonable
     // results. It would be nice to do this more elegantly.
 
-    // TODO: We should hide types associated with applications the user can
-    // not access. There's no reasonable way to do this right now.
-
     $indexers = id(new PhutilSymbolLoader())
       ->setAncestorClass('PhabricatorSearchDocumentIndexer')
       ->loadObjects();
 
-    $types = PhabricatorPHIDType::getAllTypes();
+    if ($viewer) {
+      $types = PhabricatorPHIDType::getAllInstalledTypes($viewer);
+    } else {
+      $types = PhabricatorPHIDType::getAllTypes();
+    }
 
     $results = array();
     foreach ($types as $type) {