diff --git a/src/microdot/microdot.py b/src/microdot/microdot.py
index 49128ad..3ca28e1 100644
--- a/src/microdot/microdot.py
+++ b/src/microdot/microdot.py
@@ -774,7 +774,10 @@ def send_file(cls, filename, status_code=200, content_type=None,
         first.
         """
         if content_type is None:
-            ext = filename.split('.')[-1]
+            if filename.endswith('.gz'):
+                ext = filename[:-3].split('.')[-1]
+            else:
+                ext = filename.split('.')[-1]
             if ext in Response.types_map:
                 content_type = Response.types_map[ext]
             else:
diff --git a/tests/files/test.txt.gz b/tests/files/test.txt.gz
new file mode 100644
index 0000000..1910281
--- /dev/null
+++ b/tests/files/test.txt.gz
@@ -0,0 +1 @@
+foo
\ No newline at end of file
diff --git a/tests/test_response.py b/tests/test_response.py
index 337f8dc..6f129dd 100644
--- a/tests/test_response.py
+++ b/tests/test_response.py
@@ -280,6 +280,15 @@ def test_send_file_compressed(self):
                          'application/octet-stream')
         self.assertEqual(res.headers['Content-Encoding'], 'gzip')
 
+    def test_send_file_with_correct_mime_type(self):
+        res = Response.send_file('tests/files/test.txt')
+        self.assertEqual(res.status_code, 200)
+        self.assertEqual(res.headers['Content-Type'], 'text/plain')
+
+        res = Response.send_file('tests/files/test.txt.gz')
+        self.assertEqual(res.status_code, 200)
+        self.assertEqual(res.headers['Content-Type'], 'text/plain')
+
     def test_default_content_type(self):
         original_content_type = Response.default_content_type
         res = Response('foo')