diff --git a/apps/blogs/migrations/0004_normalize_blogentry_urls.py b/apps/blogs/migrations/0004_normalize_blogentry_urls.py
new file mode 100644
index 000000000..39ddda703
--- /dev/null
+++ b/apps/blogs/migrations/0004_normalize_blogentry_urls.py
@@ -0,0 +1,32 @@
+"""Rewrite legacy pythoninsider.blogspot.com URLs to blog.python.org.
+
+Blogger's RSS feed historically served entry links under the old
+pythoninsider.blogspot.com domain.  This one-time migration normalizes
+existing BlogEntry rows so that the parser's runtime normalization
+(added in the same changeset) doesn't create duplicates via
+update_or_create.
+"""
+
+from django.db import migrations
+from django.db.models import Value
+from django.db.models.functions import Replace
+
+
+def normalize_blogentry_urls(apps, schema_editor):
+    BlogEntry = apps.get_model("blogs", "BlogEntry")
+    BlogEntry.objects.filter(url__contains="pythoninsider.blogspot.com").update(
+        url=Replace("url", Value("pythoninsider.blogspot.com"), Value("blog.python.org")),
+    )
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("blogs", "0003_alter_relatedblog_creator_and_more"),
+    ]
+
+    operations = [
+        migrations.RunPython(
+            normalize_blogentry_urls,
+            reverse_code=migrations.RunPython.noop,
+        ),
+    ]
diff --git a/apps/blogs/parser.py b/apps/blogs/parser.py
index 8f557dd9a..5efd2b99f 100644
--- a/apps/blogs/parser.py
+++ b/apps/blogs/parser.py
@@ -1,6 +1,7 @@
 """RSS feed parsing and blog supernav rendering utilities."""
 
 import datetime
+from urllib.parse import urlparse, urlunparse
 
 import feedparser
 from django.conf import settings
@@ -9,6 +10,19 @@
 from apps.blogs.models import BlogEntry, Feed
 from apps.boxes.models import Box
 
+# Blogger serves RSS entry links with this legacy domain instead of
+# the canonical blog.python.org hostname.
+_BLOGGER_LEGACY_HOST = "pythoninsider.blogspot.com"
+
+
+def _normalize_blog_url(url):
+    """Rewrite legacy Blogger URLs to the canonical blog.python.org domain."""
+    parsed = urlparse(url)
+    if parsed.hostname == _BLOGGER_LEGACY_HOST:
+        canonical = urlparse(settings.PYTHON_BLOG_URL)
+        return urlunparse(parsed._replace(scheme=canonical.scheme, netloc=canonical.netloc))
+    return url
+
 
 def get_all_entries(feed_url):
     """Retrieve all entries from a feed URL."""
@@ -22,7 +36,7 @@ def get_all_entries(feed_url):
             "title": e["title"],
             "summary": e.get("summary", ""),
             "pub_date": published,
-            "url": e["link"],
+            "url": _normalize_blog_url(e["link"]),
         }
 
         entries.append(entry)
diff --git a/apps/blogs/tests/test_parser.py b/apps/blogs/tests/test_parser.py
index 1b1a83ae8..2600d39d9 100644
--- a/apps/blogs/tests/test_parser.py
+++ b/apps/blogs/tests/test_parser.py
@@ -1,7 +1,7 @@
 import datetime
 import unittest
 
-from apps.blogs.parser import get_all_entries
+from apps.blogs.parser import _normalize_blog_url, get_all_entries
 from apps.blogs.tests.utils import get_test_rss_path
 
 
@@ -24,3 +24,27 @@ def test_entries(self):
             self.entries[0]["url"],
             "http://feedproxy.google.com/~r/PythonInsider/~3/tGNCqyOiun4/introducing-electronic-contributor.html",
         )
+
+
+class NormalizeBlogUrlTest(unittest.TestCase):
+    def test_rewrites_pythoninsider_blogspot(self):
+        url = "https://pythoninsider.blogspot.com/2026/02/join-the-python-security-response-team.html"
+        self.assertEqual(
+            _normalize_blog_url(url),
+            "https://blog.python.org/2026/02/join-the-python-security-response-team.html",
+        )
+
+    def test_rewrites_http_to_canonical_scheme(self):
+        url = "http://pythoninsider.blogspot.com/2026/01/some-post.html"
+        self.assertEqual(
+            _normalize_blog_url(url),
+            "https://blog.python.org/2026/01/some-post.html",
+        )
+
+    def test_preserves_non_blogspot_urls(self):
+        url = "http://feedproxy.google.com/~r/PythonInsider/~3/abc/some-post.html"
+        self.assertEqual(_normalize_blog_url(url), url)
+
+    def test_preserves_blog_python_org_urls(self):
+        url = "https://blog.python.org/2026/02/some-post.html"
+        self.assertEqual(_normalize_blog_url(url), url)