diff --git a/src/applications/owners/typeahead/PhabricatorOwnersPackageDatasource.php b/src/applications/owners/typeahead/PhabricatorOwnersPackageDatasource.php
--- a/src/applications/owners/typeahead/PhabricatorOwnersPackageDatasource.php
+++ b/src/applications/owners/typeahead/PhabricatorOwnersPackageDatasource.php
@@ -22,9 +22,18 @@
     $results = array();
 
     $query = id(new PhabricatorOwnersPackageQuery())
-      ->withNameNgrams($raw_query)
       ->setOrder('name');
 
+    // If the user is querying by monogram explicitly, like "O123", do an ID
+    // search. Otherwise, do an ngram substring search.
+    if (preg_match('/^[oO]\d+\z/', $raw_query)) {
+      $id = trim($raw_query, 'oO');
+      $id = (int)$id;
+      $query->withIDs(array($id));
+    } else {
+      $query->withNameNgrams($raw_query);
+    }
+
     $packages = $this->executeQuery($query);
     foreach ($packages as $package) {
       $name = $package->getName();