diff --git a/Lib/fontTools/unicodedata/__init__.py b/Lib/fontTools/unicodedata/__init__.py
index afabbed14..7998e9dd5 100644
--- a/Lib/fontTools/unicodedata/__init__.py
+++ b/Lib/fontTools/unicodedata/__init__.py
@@ -134,8 +134,10 @@ def script_code(script_name, default=KeyError):
         return default
 
 
-# The data on script direction is taken from CLDR 37:
-# https://github.com/unicode-org/cldr/blob/release-37/common/properties/scriptMetadata.txt
+# The data on script direction is taken from Harfbuzz source code:
+# https://github.com/harfbuzz/harfbuzz/blob/3.2.0/src/hb-common.cc#L514-L613
+# This in turn references the following "Script_Metadata" document:
+# https://docs.google.com/spreadsheets/d/1Y90M0Ie3MUJ6UVCRDOypOtijlMDLNNyyLk36T6iMu0o
 RTL_SCRIPTS = {
     # Unicode-1.1 additions
     'Arab',  # Arabic
@@ -200,6 +202,9 @@ RTL_SCRIPTS = {
     # Unicode-13.0 additions
     'Chrs',  # Chorasmian
     'Yezi',  # Yezidi
+
+    # Unicode-14.0 additions
+    'Ougr',  # Old Uyghur
 }
 
 def script_horizontal_direction(script_code, default=KeyError):
diff --git a/Tests/unicodedata_test.py b/Tests/unicodedata_test.py
index 2ae11beff..aac59bee8 100644
--- a/Tests/unicodedata_test.py
+++ b/Tests/unicodedata_test.py
@@ -240,6 +240,7 @@ def test_script_horizontal_direction():
     assert unicodedata.script_horizontal_direction("Latn") == "LTR"
     assert unicodedata.script_horizontal_direction("Arab") == "RTL"
     assert unicodedata.script_horizontal_direction("Thaa") == "RTL"
+    assert unicodedata.script_horizontal_direction("Ougr") == "RTL"
 
     with pytest.raises(KeyError):
         unicodedata.script_horizontal_direction("Azzz")