diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1c4896e5df..dafc14d342 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+## 0.16.22-dev0
+
+### Fixes
+
+* **Handle filenames without extensions in file type detection**
+
 ## 0.16.21
 
 ### Enhancements
diff --git a/test_unstructured/file_utils/test_filetype.py b/test_unstructured/file_utils/test_filetype.py
index 8a58e89964..4d199d05e2 100644
--- a/test_unstructured/file_utils/test_filetype.py
+++ b/test_unstructured/file_utils/test_filetype.py
@@ -609,6 +609,8 @@ def and_it_derives_the_extension_from_metadata_file_path_when_file_object_has_no
             None,
             # -- case 2: file-like object has `.name` attribute but it's value is the empty string
             "",
+            # -- case 3: file-like object has name with no extension --
+            "q3_invoices",
         ],
     )
     def and_it_returns_the_empty_string_as_the_extension_when_there_are_no_file_name_sources(
@@ -621,6 +623,26 @@ def and_it_returns_the_empty_string_as_the_extension_when_there_are_no_file_name
 
         assert _FileTypeDetectionContext(file=file).extension == ""
 
+    @pytest.mark.parametrize(
+        "file_name",
+        [
+            # -- case 1: file-like object has no `.name` attribute
+            None,
+            # -- case 2: file-like object has `.name` attribute but it's value is the empty string
+            "",
+            # -- case 3: file-like object has name with no extension --
+            "q3_invoices",
+        ],
+    )
+    def and_it_returns_the_empty_string_as_the_extension_when_there_are_no_file_name_nor_metadata(
+        self, file_name: str | None
+    ):
+        with open(example_doc_path("ideas-page.html"), "rb") as f:
+            file = io.BytesIO(f.read())
+            file.name = None
+
+        assert _FileTypeDetectionContext(file=file, metadata_file_path=file_name).extension == ""
+
     # -- .file_head ---------------------------------------------
 
     def it_grabs_the_first_8k_bytes_of_the_file_for_use_by_magic(self):
diff --git a/unstructured/__version__.py b/unstructured/__version__.py
index fb8bd1ff84..5614e0ae84 100644
--- a/unstructured/__version__.py
+++ b/unstructured/__version__.py
@@ -1 +1 @@
-__version__ = "0.16.21"  # pragma: no cover
+__version__ = "0.16.22-dev0"  # pragma: no cover
diff --git a/unstructured/file_utils/filetype.py b/unstructured/file_utils/filetype.py
index c34883daf2..1ea2e37b96 100644
--- a/unstructured/file_utils/filetype.py
+++ b/unstructured/file_utils/filetype.py
@@ -346,11 +346,15 @@ def extension(self) -> str:
         # -- get from file_path, or file when it has a name (path) --
         with self.open() as file:
             if hasattr(file, "name") and file.name:
-                return os.path.splitext(file.name)[1].lower()
+                splitext = os.path.splitext(file.name)
+                if len(splitext) > 1:
+                    return splitext[1].lower()
 
         # -- otherwise use metadata file-path when provided --
         if file_path := self._metadata_file_path:
-            return os.path.splitext(file_path)[1].lower()
+            splitext = os.path.splitext(file_path)
+            if len(splitext) > 1:
+                return splitext[1].lower()
 
         # -- otherwise empty str means no extension, same as a path like "a/b/name-no-ext" --
         return ""