diff --git a/changelog/8208.improvement.md b/changelog/8208.improvement.md
new file mode 100644
index 000000000000..309f9a04d45f
--- /dev/null
+++ b/changelog/8208.improvement.md
@@ -0,0 +1 @@
+Faster reading of YAML NLU training data files.
diff --git a/rasa/shared/core/training_data/story_reader/yaml_story_reader.py b/rasa/shared/core/training_data/story_reader/yaml_story_reader.py
index e948cfd1638e..6939fba8f754 100644
--- a/rasa/shared/core/training_data/story_reader/yaml_story_reader.py
+++ b/rasa/shared/core/training_data/story_reader/yaml_story_reader.py
@@ -160,35 +160,9 @@ def is_stories_file(cls, file_path: Union[Text, Path]) -> bool:
             YamlException: if the file seems to be a YAML file (extension) but
                 can not be read / parsed.
         """
-        return rasa.shared.data.is_likely_yaml_file(file_path) and cls.is_key_in_yaml(
-            file_path, KEY_STORIES, KEY_RULES
-        )
-
-    @classmethod
-    def is_key_in_yaml(cls, file_path: Union[Text, Path], *keys: Text) -> bool:
-        """Check if any of the keys is contained in the root object of the yaml file.
-
-        Arguments:
-            file_path: path to the yaml file
-            keys: keys to look for
-
-        Returns:
-              `True` if at least one of the keys is found, `False` otherwise.
-
-        Raises:
-            FileNotFoundException: if the file cannot be found.
-        """
-        try:
-            with open(file_path) as file:
-                return any(
-                    any(line.lstrip().startswith(f"{key}:") for key in keys)
-                    for line in file
-                )
-        except FileNotFoundError:
-            raise FileNotFoundException(
-                f"Failed to read file, "
-                f"'{os.path.abspath(file_path)}' does not exist."
-            )
+        return rasa.shared.data.is_likely_yaml_file(
+            file_path
+        ) and rasa.shared.utils.io.is_key_in_yaml(file_path, KEY_STORIES, KEY_RULES)
 
     @classmethod
     def _has_test_prefix(cls, file_path: Text) -> bool:
diff --git a/rasa/shared/nlu/training_data/formats/rasa_yaml.py b/rasa/shared/nlu/training_data/formats/rasa_yaml.py
index ed54e58a8f23..1ef6b30de36b 100644
--- a/rasa/shared/nlu/training_data/formats/rasa_yaml.py
+++ b/rasa/shared/nlu/training_data/formats/rasa_yaml.py
@@ -334,7 +334,7 @@ def _parse_multiline_example(self, item: Text, examples: Text) -> Iterator[Text]
             yield example[1:].strip(STRIP_SYMBOLS)
 
     @staticmethod
-    def is_yaml_nlu_file(filename: Text) -> bool:
+    def is_yaml_nlu_file(filename: Union[Text, Path]) -> bool:
         """Checks if the specified file possibly contains NLU training data in YAML.
 
         Args:
@@ -351,9 +351,7 @@ def is_yaml_nlu_file(filename: Text) -> bool:
         if not rasa.shared.data.is_likely_yaml_file(filename):
             return False
 
-        content = rasa.shared.utils.io.read_yaml_file(filename)
-
-        return any(key in content for key in {KEY_NLU, KEY_RESPONSES})
+        return rasa.shared.utils.io.is_key_in_yaml(filename, KEY_NLU, KEY_RESPONSES)
 
 
 class RasaYAMLWriter(TrainingDataWriter):
diff --git a/rasa/shared/utils/io.py b/rasa/shared/utils/io.py
index 91e1c3ce402d..b5de0b3a315f 100644
--- a/rasa/shared/utils/io.py
+++ b/rasa/shared/utils/io.py
@@ -414,6 +414,31 @@ def write_yaml(
 YAML_LINE_MAX_WIDTH = 4096
 
 
+def is_key_in_yaml(file_path: Union[Text, Path], *keys: Text) -> bool:
+    """Checks if any of the keys is contained in the root object of the yaml file.
+
+    Arguments:
+        file_path: path to the yaml file
+        keys: keys to look for
+
+    Returns:
+          `True` if at least one of the keys is found, `False` otherwise.
+
+    Raises:
+        FileNotFoundException: if the file cannot be found.
+    """
+    try:
+        with open(file_path) as file:
+            return any(
+                any(line.lstrip().startswith(f"{key}:") for key in keys)
+                for line in file
+            )
+    except FileNotFoundError:
+        raise FileNotFoundException(
+            f"Failed to read file, " f"'{os.path.abspath(file_path)}' does not exist."
+        )
+
+
 def convert_to_ordered_dict(obj: Any) -> Any:
     """Convert object to an `OrderedDict`.
 
diff --git a/tests/shared/core/training_data/story_reader/test_yaml_story_reader.py b/tests/shared/core/training_data/story_reader/test_yaml_story_reader.py
index ff87ecd26859..04a63630a452 100644
--- a/tests/shared/core/training_data/story_reader/test_yaml_story_reader.py
+++ b/tests/shared/core/training_data/story_reader/test_yaml_story_reader.py
@@ -204,26 +204,6 @@ async def test_is_yaml_file(file: Text, is_yaml_file: bool):
     assert YAMLStoryReader.is_stories_file(file) == is_yaml_file
 
 
-@pytest.mark.parametrize(
-    "file,keys,expected_result",
-    [
-        ("data/test_yaml_stories/stories.yml", ["stories"], True),
-        ("data/test_yaml_stories/stories.yml", ["something_else"], False),
-        ("data/test_yaml_stories/stories.yml", ["stories", "something_else"], True),
-        (
-            "data/test_domains/default_retrieval_intents.yml",
-            ["intents", "responses"],
-            True,
-        ),
-        ("data/test_yaml_stories/rules_without_stories.yml", ["rules"], True),
-        ("data/test_yaml_stories/rules_without_stories.yml", ["stories"], False),
-        ("data/test_stories/stories.md", ["something"], False),
-    ],
-)
-async def test_is_key_in_yaml(file: Text, keys: List[Text], expected_result: bool):
-    assert YAMLStoryReader.is_key_in_yaml(file, *keys) == expected_result
-
-
 async def test_yaml_intent_with_leading_slash_warning(default_domain: Domain):
     yaml_file = "data/test_wrong_yaml_stories/intent_with_leading_slash.yml"
 
diff --git a/tests/shared/nlu/training_data/formats/test_rasa_yaml.py b/tests/shared/nlu/training_data/formats/test_rasa_yaml.py
index c18f1235ed40..fa922ed6cd9a 100644
--- a/tests/shared/nlu/training_data/formats/test_rasa_yaml.py
+++ b/tests/shared/nlu/training_data/formats/test_rasa_yaml.py
@@ -360,9 +360,9 @@ def test_minimal_valid_example():
     assert not len(record)
 
 
-def test_minimal_yaml_nlu_file(tmp_path):
+def test_minimal_yaml_nlu_file(tmp_path: pathlib.Path):
     target_file = tmp_path / "test_nlu_file.yaml"
-    rasa.shared.utils.io.write_yaml(MINIMAL_VALID_EXAMPLE, target_file, True)
+    rasa.shared.utils.io.write_text_file(MINIMAL_VALID_EXAMPLE, target_file)
     assert RasaYAMLReader.is_yaml_nlu_file(target_file)
 
 
diff --git a/tests/shared/utils/test_io.py b/tests/shared/utils/test_io.py
index 600861230654..28c80031893a 100644
--- a/tests/shared/utils/test_io.py
+++ b/tests/shared/utils/test_io.py
@@ -532,3 +532,23 @@ def test_read_invalid_config_file(tmp_path: Path, content: Text):
 
     with pytest.raises(rasa.shared.utils.validation.YamlValidationException):
         rasa.shared.utils.io.read_model_configuration(config_file)
+
+
+@pytest.mark.parametrize(
+    "file,keys,expected_result",
+    [
+        ("data/test_yaml_stories/stories.yml", ["stories"], True),
+        ("data/test_yaml_stories/stories.yml", ["something_else"], False),
+        ("data/test_yaml_stories/stories.yml", ["stories", "something_else"], True),
+        (
+            "data/test_domains/default_retrieval_intents.yml",
+            ["intents", "responses"],
+            True,
+        ),
+        ("data/test_yaml_stories/rules_without_stories.yml", ["rules"], True),
+        ("data/test_yaml_stories/rules_without_stories.yml", ["stories"], False),
+        ("data/test_stories/stories.md", ["something"], False),
+    ],
+)
+async def test_is_key_in_yaml(file: Text, keys: List[Text], expected_result: bool):
+    assert rasa.shared.utils.io.is_key_in_yaml(file, *keys) == expected_result