diff --git a/changelogs/fragments/397-ansible-core-version-in-porting-guide.yml b/changelogs/fragments/397-ansible-core-version-in-porting-guide.yml
new file mode 100644
index 00000000..58d5faa4
--- /dev/null
+++ b/changelogs/fragments/397-ansible-core-version-in-porting-guide.yml
@@ -0,0 +1,2 @@
+minor_changes:
+  - "Mention the ``ansible-core`` major version in the Ansible porting guide (https://github.com/ansible-community/antsibull/pull/397)."
diff --git a/src/antsibull/build_changelog.py b/src/antsibull/build_changelog.py
index 24079af7..d24d8123 100644
--- a/src/antsibull/build_changelog.py
+++ b/src/antsibull/build_changelog.py
@@ -614,6 +614,12 @@ def _get_porting_guide_bytes(changelog: Changelog) -> bytes:
 
         # Determine whether to include ansible-core porting guide or not
         if changelog.ansible_version.major == 2 or base_version != prev_base_version:
+            if changelog.ansible_version.major > 2:
+                builder.add_raw_rst(
+                    # noqa: E501
+                    "\n"
+                    f"Ansible {version} is based on Ansible-core {base_version}."
+                    "\n")
             builder.add_raw_rst(
                 # noqa: E501
                 "\n"