diff --git a/RELEASE-NOTES-1.33 b/RELEASE-NOTES-1.33
index 9a974eeddd5..52eaf9e5e0d 100644
--- a/RELEASE-NOTES-1.33
+++ b/RELEASE-NOTES-1.33
@@ -133,6 +133,7 @@ because of Phabricator reports.
 * (T213717) Fixed a translation error on Goan Konkani (gom-deva) translations
   for NS_TEMPLATE.
 * (T212221) Added $digitTransformTable for Santali (sat).
+* (T216479) Added language support for Saisiyat (xsy).
 
 === Breaking changes in 1.33 ===
 * The parameteter $lang in DifferenceEngine::setTextLanguage must be of type
diff --git a/languages/data/Names.php b/languages/data/Names.php
index aaa5d169829..868b746c0ae 100644
--- a/languages/data/Names.php
+++ b/languages/data/Names.php
@@ -469,6 +469,7 @@ class Names {
 		'xal' => 'хальмг', # Kalmyk-Oirat
 		'xh' => 'isiXhosa', # Xhosan
 		'xmf' => 'მარგალური', # Mingrelian
+		'xsy' => 'saisiyat', # SaiSiyat - T216479
 		'yi' => 'ייִדיש', # Yiddish
 		'yo' => 'Yorùbá', # Yoruba
 		'yue' => '粵語', # Cantonese
diff --git a/languages/messages/MessagesXsy.php b/languages/messages/MessagesXsy.php
new file mode 100644
index 00000000000..f78232c5c62
--- /dev/null
+++ b/languages/messages/MessagesXsy.php
@@ -0,0 +1,9 @@
+<?php
+/** Saisiyat
+ *
+ * To improve a translation please visit https://translatewiki.net
+ *
+ * @ingroup Language
+ * @file
+ *
+ */