diff --git a/tools/lib/template_parser.py b/tools/lib/template_parser.py
index 670642f0b9..1f09aaab8e 100644
--- a/tools/lib/template_parser.py
+++ b/tools/lib/template_parser.py
@@ -75,6 +75,9 @@ def tokenize(text: str) -> List[Token]:
     def looking_at_handlebars_partial() -> bool:
         return looking_at("{{>")
 
+    def looking_at_handlebars_partial_block() -> bool:
+        return looking_at("{{#>")
+
     def looking_at_html_start() -> bool:
         return looking_at("<") and not looking_at("</")
 
@@ -140,6 +143,10 @@ def tokenize(text: str) -> List[Token]:
                 s = get_handlebars_partial(text, state.i)
                 tag = s[9:-2]
                 kind = "handlebars_partial"
+            elif looking_at_handlebars_partial_block():
+                s = get_handlebars_partial(text, state.i)
+                tag = s[5:-2]
+                kind = "handlebars_partial_block"
             elif looking_at_html_start():
                 s = get_html_tag(text, state.i)
                 if s.endswith("/>"):
@@ -311,7 +318,7 @@ def tag_flavor(token: Token) -> Optional[str]:
     ):
         return None
 
-    if kind in ("handlebars_start", "html_start"):
+    if kind in ("handlebars_start", "handlebars_partial_block", "html_start"):
         return "start"
     elif kind in (
         "django_else",
@@ -726,6 +733,7 @@ def get_django_comment(text: str, i: int) -> str:
 
 
 def get_handlebars_partial(text: str, i: int) -> str:
+    """Works for both partials and partial blocks."""
     end = i + 10
     unclosed_end = 0
     while end <= len(text):
diff --git a/tools/tests/test_template_parser.py b/tools/tests/test_template_parser.py
index e3db01540f..30c82db36f 100644
--- a/tools/tests/test_template_parser.py
+++ b/tools/tests/test_template_parser.py
@@ -49,6 +49,22 @@ class ParserTest(unittest.TestCase):
             """
         validate(text=my_html)
 
+    def test_validate_handlebars_partial_block(self) -> None:
+        my_html = """
+            {{#> generic_thing }}
+                <p>hello!</p>
+            {{/generic_thing}}
+            """
+        validate(text=my_html)
+
+    def test_validate_bad_handlebars_partial_block(self) -> None:
+        my_html = """
+            {{#> generic_thing }}
+                <p>hello!</p>
+            {{# generic_thing}}
+            """
+        self._assert_validate_error("Missing end tag for the token at row 4 13!", text=my_html)
+
     def test_validate_comment(self) -> None:
         my_html = """
             <!---
@@ -298,6 +314,11 @@ class ParserTest(unittest.TestCase):
         self.assertEqual(token.kind, "handlebars_end")
         self.assertEqual(token.tag, "with")
 
+        tag = "{{#> compose_banner }}bla"
+        token = tokenize(tag)[0]
+        self.assertEqual(token.kind, "handlebars_partial_block")
+        self.assertEqual(token.tag, "compose_banner")
+
         tag = "{% if foo %}bla"
         token = tokenize(tag)[0]
         self.assertEqual(token.kind, "django_start")