diff --git a/src/applications/config/check/PhabricatorSetupCheckMySQL.php b/src/applications/config/check/PhabricatorSetupCheckMySQL.php
index 9ea3ca6f6d..16a5438cee 100644
--- a/src/applications/config/check/PhabricatorSetupCheckMySQL.php
+++ b/src/applications/config/check/PhabricatorSetupCheckMySQL.php
@@ -226,6 +226,41 @@ final class PhabricatorSetupCheckMySQL extends PhabricatorSetupCheck {
       }
     }
 
+    $bool_syntax = self::loadRawConfigValue('ft_boolean_syntax');
+    if ($bool_syntax != ' |-><()~*:""&^') {
+      if (!PhabricatorDefaultSearchEngineSelector::shouldUseElasticSearch()) {
+
+        $summary = pht(
+          'MySQL is configured to search on fulltext indexes using "OR" by '.
+          'default. Using "AND" is usually the desired behaviour.');
+
+        $message = pht(
+          "Your MySQL instance is configured to use the default Boolean ".
+          "search syntax when using fulltext indexes. This means searching ".
+          "for 'search words' will yield the query 'search OR words' ".
+          "instead of the desired 'search AND words'.\n\n".
+          "This might produce unexpected search results. \n\n".
+          "You can change this setting to a more sensible default. ".
+          "Alternatively, you can ignore this warning if ".
+          "using 'OR' is the desired behaviour. If you later plan ".
+          "to configure ElasticSearch, you can also ignore this warning: ".
+          "only MySQL fulltext search is affected.\n\n".
+          "To change this setting, add this to your %s file ".
+          "(in the %s section) and then restart %s:\n\n".
+          "%s\n",
+          phutil_tag('tt', array(), 'my.cnf'),
+          phutil_tag('tt', array(), '[mysqld]'),
+          phutil_tag('tt', array(), 'mysqld'),
+          phutil_tag('pre', array(), 'ft_boolean_syntax=\' |-><()~*:""&^\''));
+
+        $this->newIssue('mysql.ft_boolean_syntax')
+          ->setName(pht('MySQL is Using the Default Boolean Syntax'))
+          ->setSummary($summary)
+          ->setMessage($message)
+          ->addMySQLConfig('ft_boolean_syntax');
+      }
+    }
+
     $innodb_pool = self::loadRawConfigValue('innodb_buffer_pool_size');
     $innodb_bytes = phutil_parse_bytes($innodb_pool);
     $innodb_readable = phutil_format_bytes($innodb_bytes);