diff --git a/libraries/constants.py b/libraries/constants.py
index 51d2fbcbc..9b4fb744d 100644
--- a/libraries/constants.py
+++ b/libraries/constants.py
@@ -346,9 +346,12 @@
 # List of versions for which we know docs are missing
 VERSION_DOCS_MISSING = ["boost-1.33.0"]
 
+# File paths where library description content might be stored, in priority order.
+DESCRIPTION_FILES = ["doc/library-detail.adoc", "README.md", "README.adoc"]
+
 # This constant is for library-versions missing a README
 README_MISSING = (
-    "⚠️ This library has no README.md or library-details.adoc; "
+    "⚠️ This library has no README file or library-detail.adoc; "
     "consider contributing one."
 )
 
diff --git a/libraries/models.py b/libraries/models.py
index bfd10139a..9f42716c1 100644
--- a/libraries/models.py
+++ b/libraries/models.py
@@ -25,7 +25,7 @@
 from libraries.managers import IssueManager
 from mailing_list.models import EmailData
 from versions.models import ReportConfiguration
-from .constants import LIBRARY_GITHUB_URL_OVERRIDES
+from .constants import DESCRIPTION_FILES, LIBRARY_GITHUB_URL_OVERRIDES
 
 from .utils import (
     generate_random_string,
@@ -335,13 +335,12 @@ def save(self, *args, **kwargs):
     def get_description(self, client, tag="develop"):
         """Get description from the appropriate file on GitHub.
 
-        For more recent versions, that will be `/doc/library-details.adoc`.
+        For more recent versions, that will be `/doc/library-detail.adoc`.
         For older versions, or libraries that have not adopted the adoc file,
-        that will be `/README.md`.
+        that will be `/README.md` or `/README.adoc`.
         """
         content = None
-        # File paths/names where description data might be stored.
-        files = ["doc/library-detail.adoc", "README.md"]
+        files = DESCRIPTION_FILES
 
         # Try to get the content from the cache first
         static_content_cache = caches["static_content"]
diff --git a/libraries/tests/test_models.py b/libraries/tests/test_models.py
index 441e65933..103b0aaba 100644
--- a/libraries/tests/test_models.py
+++ b/libraries/tests/test_models.py
@@ -1,7 +1,13 @@
 import datetime
+from unittest.mock import MagicMock, patch
+
+import pytest
+from django.core.cache import caches
 from django.db.models import Sum
 from model_bakery import baker
 
+from core.models import RenderedContent
+from libraries.constants import DESCRIPTION_FILES
 from libraries.models import CommitAuthor
 from mailing_list.models import EmailData
 
@@ -140,6 +146,34 @@ def test_library_version_first_boost_version_property(library):
     assert library.first_boost_version == version_3
 
 
+@pytest.mark.parametrize(
+    "first_available, expected",
+    [(0, "<p>adoc</p>"), (1, "<p>md</p>"), (2, "<p>adoc</p>"), (None, None)],
+    ids=["library-detail.adoc", "README.md-fallback", "README.adoc-fallback", "none"],
+)
+@patch("libraries.models.process_md", return_value=("", "<p>md</p>"))
+@patch("libraries.models.write_content_to_tempfile")
+@patch("libraries.models.convert_adoc_to_html", return_value="<p>adoc</p>")
+def test_get_description_file_priority(
+    _adoc, mock_tempfile, _md, library, first_available, expected
+):
+    """Files are tried in order; the first available file wins."""
+    caches["static_content"].clear()
+    RenderedContent.objects.all().delete()
+    mock_tempfile.return_value.name = "/tmp/fake"
+
+    available = dict.fromkeys(DESCRIPTION_FILES)
+    if first_available is not None:
+        for f in DESCRIPTION_FILES[first_available:]:
+            available[f] = b"content"
+
+    client = MagicMock()
+    client.get_file_content.side_effect = (
+        lambda repo_slug, tag, file_path: available.get(file_path)
+    )
+    assert library.get_description(client) == expected
+
+
 def test_merge_author_deletes_author():
     author_1_email = baker.make("libraries.CommitAuthorEmail")
     author_1 = author_1_email.author