diff --git a/tensorflow_datasets/core/download/resource.py b/tensorflow_datasets/core/download/resource.py
index a3c35f225fa..58f779be489 100644
--- a/tensorflow_datasets/core/download/resource.py
+++ b/tensorflow_datasets/core/download/resource.py
@@ -139,15 +139,21 @@ def _sanitize_url(url, max_length):
   for suffix in _NETLOC_COMMON_SUFFIXES:
     if netloc.endswith(suffix):
       netloc = netloc[:-len(suffix)]
-  url = '%s%s%s%s' % (netloc, url.path, url.params, url.query)
+  path = url.path
   # Get the extension:
   for ext in _KNOWN_EXTENSIONS:
-    if url.endswith(ext):
+    if path.endswith(ext):
       extension = ext
-      url = url[:-len(extension)]
+      path = path[:-len(extension)]
       break
   else:
-    url, extension = os.path.splitext(url)
+    path, extension = os.path.splitext(path)
+    if len(extension) >= max_length:
+      # If the extension is this long, the remaining url would be empty and the extension
+      # is most likely not actually an extension but the final part of a filename without
+      # an extension but with dot separators, so we clear the extension
+      path, extension = url.path, ""
+  url = '%s%s%s%s' % (netloc, path, url.params, url.query)
   max_length -= len(extension)
   # Replace non authorized chars (including '/') by '_':
   url = re.sub(r'[^a-zA-Z0-9\.\-_]+', '_', url)
diff --git a/tensorflow_datasets/core/download/resource_test.py b/tensorflow_datasets/core/download/resource_test.py
index 56414688288..4b493d22b81 100644
--- a/tensorflow_datasets/core/download/resource_test.py
+++ b/tensorflow_datasets/core/download/resource_test.py
@@ -57,7 +57,9 @@ class DlDirNameTest(testing.TestCase):
 https://rajpurkar.github.io/SQuAD-explorer/dataset/train-v1.1.json
 https://storage.googleapis.com/scv_dataset/data/Brawl_64x64_png/valid-00000-of-00001.tfrecords
 https://storage.googleapis.com/scv_dataset/data/CollectMineralShards_128x128_png/train-00005-of-00010.tfrecords
-https://www.cs.toronto.edu/~kriz/cifar-100-python.tar.gz\
+https://www.cs.toronto.edu/~kriz/cifar-100-python.tar.gz
+https://somehost.example.com/path/to/file.tar.gz?query-parameters=value&parameter-with-a-dot=size-12.5&and-more-parameters=with-their-values&is-this-the-extension=no
+https://somehost.example.com/path/to/file.with-no-extension-but-a-dot-somewhere-and-the-whole-thing-is-longer-than-the-maximum-allowed-characters\
 """.split('\n')
   expected = """\
 data.statmt.org_wmt17_translation-task_devDjZ11PU9sKPPvF2sZTAzTsV7Pi3IYHaPDMOoeEuby2E.tgz
@@ -73,7 +75,9 @@ class DlDirNameTest(testing.TestCase):
 rajpurkar_SQuAD-explorer_train-v1.1uLsZc14btZFRCgHMAy9Mn5abwO6wga4bMozTBvOyQAg.json
 scv_Brawl_64x64_png_valid-0_1Ez3yPwN0QDCxBd0xHeLb2DfUERJjkqFd2dyL5Z7-ULg.tfrecords
 scv_CollectMi_128x128_png_train-5_10kiunW_2RTDhXuPrxCVkUZKCoWpADYBUWE8DpraC8zAA.tfrecords
-cs.toronto.edu_kriz_cifar-100-pythonJDFhDchdt5UW8GUAkvf_-H_r_LnFs6sHlOrqTidrpSI.tar.gz\
+cs.toronto.edu_kriz_cifar-100-pythonJDFhDchdt5UW8GUAkvf_-H_r_LnFs6sHlOrqTidrpSI.tar.gz
+some.exam.com_path_to_file-para_valu_pa6KFrwWxom3oLGuRv2mHErUlx3XXd-jwJWlgvHMXh2Yc.tar.gz
+some.exam.com_path_to_file.with-no-exte-but-a-gSqjzNXcNOyu4vaF84g8NRJtgyCH2Lt6bn0PCyvvlMk\
 """.split('\n')
 
   def test_(self):