diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -2525,6 +2525,7 @@
     'PhabricatorSearchRelationship' => 'applications/search/constants/PhabricatorSearchRelationship.php',
     'PhabricatorSearchResultView' => 'applications/search/view/PhabricatorSearchResultView.php',
     'PhabricatorSearchSelectController' => 'applications/search/controller/PhabricatorSearchSelectController.php',
+    'PhabricatorSearchSpacesField' => 'applications/search/field/PhabricatorSearchSpacesField.php',
     'PhabricatorSearchStringListField' => 'applications/search/field/PhabricatorSearchStringListField.php',
     'PhabricatorSearchTokenizerField' => 'applications/search/field/PhabricatorSearchTokenizerField.php',
     'PhabricatorSearchUsersField' => 'applications/search/field/PhabricatorSearchUsersField.php',
@@ -2578,6 +2579,7 @@
     'PhabricatorSpacesInterface' => 'applications/spaces/interface/PhabricatorSpacesInterface.php',
     'PhabricatorSpacesListController' => 'applications/spaces/controller/PhabricatorSpacesListController.php',
     'PhabricatorSpacesNamespace' => 'applications/spaces/storage/PhabricatorSpacesNamespace.php',
+    'PhabricatorSpacesNamespaceDatasource' => 'applications/spaces/typeahead/PhabricatorSpacesNamespaceDatasource.php',
     'PhabricatorSpacesNamespaceEditor' => 'applications/spaces/editor/PhabricatorSpacesNamespaceEditor.php',
     'PhabricatorSpacesNamespacePHIDType' => 'applications/spaces/phid/PhabricatorSpacesNamespacePHIDType.php',
     'PhabricatorSpacesNamespaceQuery' => 'applications/spaces/query/PhabricatorSpacesNamespaceQuery.php',
@@ -6020,6 +6022,7 @@
     'PhabricatorSearchPreferencesSettingsPanel' => 'PhabricatorSettingsPanel',
     'PhabricatorSearchResultView' => 'AphrontView',
     'PhabricatorSearchSelectController' => 'PhabricatorSearchBaseController',
+    'PhabricatorSearchSpacesField' => 'PhabricatorSearchTokenizerField',
     'PhabricatorSearchStringListField' => 'PhabricatorSearchField',
     'PhabricatorSearchTokenizerField' => 'PhabricatorSearchField',
     'PhabricatorSearchUsersField' => 'PhabricatorSearchTokenizerField',
@@ -6083,6 +6086,7 @@
       'PhabricatorApplicationTransactionInterface',
       'PhabricatorDestructibleInterface',
     ),
+    'PhabricatorSpacesNamespaceDatasource' => 'PhabricatorTypeaheadDatasource',
     'PhabricatorSpacesNamespaceEditor' => 'PhabricatorApplicationTransactionEditor',
     'PhabricatorSpacesNamespacePHIDType' => 'PhabricatorPHIDType',
     'PhabricatorSpacesNamespaceQuery' => 'PhabricatorCursorPagedPolicyAwareQuery',
diff --git a/src/applications/paste/query/PhabricatorPasteSearchEngine.php b/src/applications/paste/query/PhabricatorPasteSearchEngine.php
--- a/src/applications/paste/query/PhabricatorPasteSearchEngine.php
+++ b/src/applications/paste/query/PhabricatorPasteSearchEngine.php
@@ -11,6 +11,10 @@
     return 'PhabricatorPasteApplication';
   }
 
+  public function newResultObject() {
+    return new PhabricatorPaste();
+  }
+
   public function buildQueryFromParameters(array $map) {
     $query = id(new PhabricatorPasteQuery())
       ->needContent(true);
diff --git a/src/applications/search/engine/PhabricatorApplicationSearchEngine.php b/src/applications/search/engine/PhabricatorApplicationSearchEngine.php
--- a/src/applications/search/engine/PhabricatorApplicationSearchEngine.php
+++ b/src/applications/search/engine/PhabricatorApplicationSearchEngine.php
@@ -26,6 +26,10 @@
   const CONTEXT_LIST  = 'list';
   const CONTEXT_PANEL = 'panel';
 
+  public function newResultObject() {
+    return null;
+  }
+
   public function setViewer(PhabricatorUser $viewer) {
     $this->viewer = $viewer;
     return $this;
@@ -102,7 +106,20 @@
       $parameters[$field->getKey()] = $value;
     }
 
-    return $this->buildQueryFromParameters($parameters);
+    $query = $this->buildQueryFromParameters($parameters);
+
+    $object = $this->newResultObject();
+    if (!$object) {
+      return $query;
+    }
+
+    if ($object instanceof PhabricatorSpacesInterface) {
+      if (!empty($parameters['spacePHIDs'])) {
+        $query->withSpacePHIDs($parameters['spacePHIDs']);
+      }
+    }
+
+    return $query;
   }
 
   protected function buildQueryFromParameters(array $parameters) {
@@ -146,6 +163,20 @@
       $fields[] = $field;
     }
 
+    $object = $this->newResultObject();
+    if (!$object) {
+      return $fields;
+    }
+
+    if ($object instanceof PhabricatorSpacesInterface) {
+      if (PhabricatorSpacesNamespaceQuery::getSpacesExist()) {
+        $fields[] = id(new PhabricatorSearchSpacesField())
+          ->setKey('spacePHIDs')
+          ->setAliases(array('space', 'spaces'))
+          ->setLabel(pht('Spaces'));
+      }
+    }
+
     return $fields;
   }
 
@@ -893,6 +924,10 @@
    * @task appsearch
    */
   public function getCustomFieldObject() {
+    $object = $this->newResultObject();
+    if ($object instanceof PhabricatorCustomFieldInterface) {
+      return $object;
+    }
     return null;
   }
 
diff --git a/src/applications/search/field/PhabricatorSearchSpacesField.php b/src/applications/search/field/PhabricatorSearchSpacesField.php
new file mode 100644
--- /dev/null
+++ b/src/applications/search/field/PhabricatorSearchSpacesField.php
@@ -0,0 +1,43 @@
+<?php
+
+final class PhabricatorSearchSpacesField
+  extends PhabricatorSearchTokenizerField {
+
+  protected function getDefaultValue() {
+    return array();
+  }
+
+  protected function newDatasource() {
+    return new PhabricatorSpacesNamespaceDatasource();
+  }
+
+  protected function getValueFromRequest(AphrontRequest $request, $key) {
+    $viewer = $this->getViewer();
+    $list = $this->getListFromRequest($request, $key);
+
+    $type = new PhabricatorSpacesNamespacePHIDType();
+    $phids = array();
+    $names = array();
+    foreach ($list as $item) {
+      if ($type->canLoadNamedObject($item)) {
+        $names[] = $item;
+      } else {
+        $phids[] = $item;
+      }
+    }
+
+    if ($names) {
+      $spaces = id(new PhabricatorObjectQuery())
+        ->setViewer($viewer)
+        ->withNames($names)
+        ->execute();
+      foreach (mpull($spaces, 'getPHID') as $phid) {
+        $phids[] = $phid;
+      }
+      $phids = array_unique($phids);
+    }
+
+    return $phids;
+  }
+
+}
diff --git a/src/applications/spaces/phid/PhabricatorSpacesNamespacePHIDType.php b/src/applications/spaces/phid/PhabricatorSpacesNamespacePHIDType.php
--- a/src/applications/spaces/phid/PhabricatorSpacesNamespacePHIDType.php
+++ b/src/applications/spaces/phid/PhabricatorSpacesNamespacePHIDType.php
@@ -9,6 +9,10 @@
     return pht('Space');
   }
 
+  public function getPHIDTypeApplicationClass() {
+    return 'PhabricatorSpacesApplication';
+  }
+
   public function newObject() {
     return new PhabricatorSpacesNamespace();
   }
diff --git a/src/applications/spaces/query/PhabricatorSpacesNamespaceQuery.php b/src/applications/spaces/query/PhabricatorSpacesNamespaceQuery.php
--- a/src/applications/spaces/query/PhabricatorSpacesNamespaceQuery.php
+++ b/src/applications/spaces/query/PhabricatorSpacesNamespaceQuery.php
@@ -86,6 +86,10 @@
       ));
   }
 
+  public static function getSpacesExist() {
+    return (bool)self::getAllSpaces();
+  }
+
   public static function getAllSpaces() {
     $cache = PhabricatorCaches::getRequestCache();
     $cache_key = self::KEY_ALL;
diff --git a/src/applications/spaces/typeahead/PhabricatorSpacesNamespaceDatasource.php b/src/applications/spaces/typeahead/PhabricatorSpacesNamespaceDatasource.php
new file mode 100644
--- /dev/null
+++ b/src/applications/spaces/typeahead/PhabricatorSpacesNamespaceDatasource.php
@@ -0,0 +1,32 @@
+<?php
+
+final class PhabricatorSpacesNamespaceDatasource
+  extends PhabricatorTypeaheadDatasource {
+
+  public function getBrowseTitle() {
+    return pht('Browse Spaces');
+  }
+
+  public function getPlaceholderText() {
+    return pht('Type a space name...');
+  }
+
+  public function getDatasourceApplicationClass() {
+    return 'PhabricatorSpacesApplication';
+  }
+
+  public function loadResults() {
+    $query = id(new PhabricatorSpacesNamespaceQuery());
+
+    $spaces = $this->executeQuery($query);
+    $results = array();
+    foreach ($spaces as $space) {
+      $results[] = id(new PhabricatorTypeaheadResult())
+        ->setName($space->getNamespaceName())
+        ->setPHID($space->getPHID());
+    }
+
+    return $this->filterResultsAgainstTokens($results);
+  }
+
+}